RiceWiki - User contributions [en]

Os06g0213100

2014-05-29T08:32:03Z

Zqlyf: /* Transformation */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].

[[File:zq6.png]]

Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University

School of Life Sciences, Chinese University of Hong Kong

National Maize Improvement Center of China, China Agricultural University

Key Laboratory of Plant Functional Genomics, Ministry of Education of China

Jiangsu Key Laboratory of Crop Genetics and Physiology

Yangzhou University

Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).

[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).

[3]. D. Bikard et al., Science 323, 623 (2009).

[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).

[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).

[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).

[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086.

[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340.

Os06g0213100

2014-05-29T08:31:48Z

Zqlyf: /* Transformation */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq6.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University

School of Life Sciences, Chinese University of Hong Kong

National Maize Improvement Center of China, China Agricultural University

Key Laboratory of Plant Functional Genomics, Ministry of Education of China

Jiangsu Key Laboratory of Crop Genetics and Physiology

Yangzhou University

Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).

[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).

[3]. D. Bikard et al., Science 323, 623 (2009).

[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).

[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).

[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).

[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086.

[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340.

File:Zq6.png

2014-05-29T08:31:16Z

Zqlyf:

Os06g0213100

2014-05-29T08:27:44Z

Zqlyf: /* Labs working on this gene */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University

School of Life Sciences, Chinese University of Hong Kong

National Maize Improvement Center of China, China Agricultural University

Key Laboratory of Plant Functional Genomics, Ministry of Education of China

Jiangsu Key Laboratory of Crop Genetics and Physiology

Yangzhou University

Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).

[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).

[3]. D. Bikard et al., Science 323, 623 (2009).

[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).

[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).

[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).

[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086.

[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340.

Os06g0213100

2014-05-29T08:27:03Z

Zqlyf: /* Reference */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).

[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).

[3]. D. Bikard et al., Science 323, 623 (2009).

[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).

[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).

[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).

[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086.

[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340.

Os06g0213100

2014-05-29T08:26:44Z

Zqlyf: /* Reference */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).

[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).

[3]. D. Bikard et al., Science 323, 623 (2009).

[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

Os06g0213100

2014-05-29T08:22:50Z

Zqlyf: /* Expression */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).

[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.

[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

Os06g0213100

2014-05-29T08:21:29Z

Zqlyf: /* Transformation */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).
[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.
[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.png]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

Os06g0213100

2014-05-29T08:20:35Z

Zqlyf: /* Expression */

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).
[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.
[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.png]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.jpg]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

File:Zq4.png

2014-05-29T08:20:03Z

Zqlyf: uploaded a new version of "File:Zq4.png"

Os06g0213100

2014-05-29T08:16:59Z

Zqlyf:

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:zq1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
==Expression==
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).
[[File:zq2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.
[[File:zq3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 1A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 1B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 1C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:zq4.jpg]]

Figure1. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

==Transformation==
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:zq5.jpg]]
Fig.2. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

==Labs working on this gene==
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)

==Reference==
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

File:Zq5.png

2014-05-29T08:12:22Z

Zqlyf:

File:Zq4.png

2014-05-29T08:11:54Z

Zqlyf:

File:Zq3.jpg

2014-05-29T08:11:34Z

Zqlyf:

File:Zq2.jpg

2014-05-29T08:11:15Z

Zqlyf:

File:Zq1.jpg

2014-05-29T08:10:37Z

Zqlyf:

Os06g0213100

2014-05-29T08:07:47Z

Zqlyf:

==Introduction==
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
[[File:1.jpg]]

==Function==
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
3、Expression
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).
[[File:2.jpg]]

APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.
[[File:3.jpg]]

A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 5A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 5B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 5C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
[[File:4.jpg]]

Figure 5. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

4、Transformation
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
[[File:5.jpg]]
Fig. 1. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)
Reference
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

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2014-05-29T08:03:00Z

Zqlyf: Created page with "1、Introduction Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybr..."

1、Introduction
Reproductive isolation is both an indicator of speciation and a mechanism for maintaining species identity. The Dobzhansky- Mullermodel [1] suggests that hybrid incompatibility results fromdeleterious interactions between independently evolved loci fromdiverged populations. Studies in animal models such as Drosophila and mice have identified several of such interactive genes that cause hybrid incompatibility and segregation distortion. In plants, hybrid sterility is a major form of postzygotic reproductive isolation, and several genes have been identified that conform to the Dobzhansky-Muller model for reproductive isolation[2-5]. Hybrid sterility between indica and japonica subspecies of cultivated rice (Oryza sativa L.) is one example of postzygotic reproductive isolation in plants. Genetic analyses of indica-japonica hybrids have identified a large number of loci conditioning hybrid sterility. Several genes for indica-japonica hybrid sterility and interspecific hybrid sterility between O. sativa and O. Glumaepatula[6] were recently cloned, aiding in our understanding of the biological processes of hybrid sterility in rice species.
S5 is a major locus for hybrid sterility in rice that affects embryo-sac fertility, as identified in a number of studies across a range of germplasms. The S5 locus has three alleles, an indica allele S5-i, a japonica allele S5-j, and a neutral allele S5-n. Hybrids of genotype S5-i/S5-j are mostly sterile, whereas hybrids of genotypes consisting of S5-n with either S5-i or S5-j are mostly fertile. The S5 region has been mapped and covers up to five open reading frames (ORF1 to ORF5). Transformation studies of ORF3 to ORF5 from an indica variety into a japonica variety showed reduced fertility, due to embryo-sac abortion, for transformants harboring indica ORF5, whereas the fertility of transformants of ORF3 and ORF4 was not affected. The indica and japonica alleles of ORF5, which encodes an aspartic protease, differ by two nucleotides, whereas the wide compatibility allele has a large deletion in the N terminus of the predicted protein, causing subcellular mislocalization of the protein[7].
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2、Function
Hybrid sterility is a major form of postzygotic reproductive isolation that restricts gene flow between populations. Cultivated rice (Oryza sativa L.) consists of two subspecies, indica and japonica; inter-subspecific hybrids are usually sterile. We show that a killer-protector system at the S5 locus encoded by three tightly linked genes [Open Reading Frame 3 (ORF3) to ORF5] regulates fertility in indica-japonica hybrids. During female sporogenesis, the action of ORF5+ (killer) and ORF4+ (partner) causes endoplasmic reticulum (ER) stress. ORF3+ (protector) prevents ER stress and produces normal gametes, but ORF3– cannot prevent ER stress, resulting in premature programmed cell death and leads to embryo-sac abortion. Preferential transmission of ORF3+ gametes results in segregation distortion in the progeny. These results add to our understanding of differences between indica and japonica rice and may aid in rice genetic improvement[7].
3、Expression
For the S5iS5j genotype, the two S5 alleles had complementary patterns of expression. S5j expression was highest at stage 1 and gradually diminished during subsequent developmental stages. In contrast, S5i expression gradually increased during development, reaching a maximal value at stage 4 (Fig. 2A). These patterns are quite consistent with those observed for the parental lines Nanjing11 (S5i) and Balilla (S5j). The situation was quite different, however, for the S5jS5n genotype. S5j expression was highest at stage 1 (as seen before) but relatively low during stages 2 to 4. Throughout the developmental time course, S5n expression was reduced compared with S5j and was very low at stage 1 (Fig.2B).
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APs encoded by the three S5 alleles were analyzed by western blotting. The most dramatic difference among these proteins was associated with an approximately 24-kD isoform of AP (Fig. 3), which corresponds to the lytic AP product. At stage 4, there were distinct 24-kD isoforms of AP in samples derived from Nanjing11 and two WCVs (02428 and Dular). For Balilla samples, however, only faint 24-kD bands were detected (Fig. 3A). We extended our analysis by comparing spikelet.
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A similar result was seen with S5j-encoded AP, whereas the S5n-encoded AP was not able to dimerize (Fig. 5A). In addition, interactions between S5i- and S5j-encoded APs were detected. S5n-encoded AP, however, was unable to interact with either the S5i- or S5j-encoded AP (Fig. 5B). For each experiment, similar results were obtained when the bait and prey were switched. And the interaction was further confirmed by the growth of positive yeast clones on selective medium (Fig. 5C). These findings implied that S5-encoded APs (the S5iand S5j-encoded versions) may physically interact in plant cells to form homodimers or heterodimers (depending on the genetic context)[7].
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Figure 5. Protein-protein interactions between S5-encoded APs. A and B, The yeast two-hybrid system was used to detect interactions between S5-encoded APs. Both homophilic (A) and heterophilic (B) interactions were investigated. Yeast clones with a blue color indicate an interaction, whereas white clones denote the lack of an interaction. C, Yeast clones containing interacting baits and preys can grow well on selective medium yeast nitrogen base(Gal)-Ura-His-Trp-Leu. Sector 1, S5i + S5i;sector 2, S5i + S5j; sector 3, S5j + S5j; sector 4, positive control.

4、Transformation
Sequence polymorphisms with predictable functional changes among the genotypes in the predicted proteins were observed in ORF3 and ORF4 but not ORF1 or ORF2 (fig. S1). By investigating the transcripts, we observed that the translation start codons of ORF4 and ORF5 were located only 0.8 kb away, but the genes were transcribed in opposite directions. The ORF4 sequence of Balilla and 02428 was predicted to encode a protein with a transmembrane domain and had no homology with any known proteins (fig. S2). An 11–base pair (bp) deletion predicted to cause premature termination of the predicted protein and a loss of the putative transmembrane domain (fig. S2) was detected in ORF4 of Nanjing 11 and Dular relative to Balilla and 02428 (fig. S1). ORF3 was mapped 11.7 kb away from ORF4 and showed homology to a heat shock protein Hsp70 gene. The ORF3 sequences of Balilla and Dular have a 13-bp deletion relative to the other two genotypes (fig. S1), which results in a frameshift in the C terminus of the protein (fig. S3). On the basis of the sequence differences in these ORFs (fig. S1), we designated the ORF3 allele from Nanjing 11 and 02428 as ORF3+ and the other allele as ORF3–; the ORF4 allele from Balilla and 02428 as ORF4+ and the other one as ORF4–; and the ORF5 allele from Nanjing 11 as ORF5+, the one from Balilla as ORF5–, and those from Dular and 02428 as ORF5n[8].
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Fig. 1. Schematic representation of the killer-protector system in an indicajaponica hybrid regulated by the S5 locus. (A) A genetic model depicting the process of megaspore formation and effects of the three genes, where 3+, 3–, 4+, 4–, 5+, and 5– represent ORF3+, ORF3–, ORF4+, ORF4–, ORF5+, and ORF5–, respectively, and colored blocks and circles represent the proteins. In the megaspore mother cell and daughter cells immediately after meiotic division, killing would not occur because of the presence of ORF3+. Killing would occur in the daughter cell carrying ORF3– and ORF4+ at a later stage of megaspore development. (B) Hypothetical molecular processes involving ER-stress and PCD. bZIP50-S, spliced bZIP50; ER, endoplasmic reticulum; PM, plasma membrane.

National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University
School of Life Sciences, Chinese University of Hong Kong
National Maize Improvement Center of China, China Agricultural University,
Key Laboratory of Plant Functional Genomics, Ministry of Education of China
Jiangsu Key Laboratory of Crop Genetics and Physiology
Yangzhou University
Beijing Key Laboratory of Crop Genetic Improvement, Beijing 100193, People’s Republic of China (M.X.)
Reference
[1]. J. A. Coyne, H. A. Orr, Speciation (Sinauer Associates, Sunderland, MA, 2004).
[2]. K. Bomblies, D. Weigel, Nat. Rev. Genet. 8, 382 (2007).
[3]. D. Bikard et al., Science 323, 623 (2009).
[4]. R. Alcázar, A. V. García, J. E. Parker, M. Reymond, Proc. Natl. Acad. Sci. U.S.A. 106, 334 (2009).
[5]. K. Bomblies, Annu. Rev. Plant Biol. 61, 109 (2010).
[6].Y. Yamagata et al., Proc. Natl. Acad. Sci. U.S.A. 107, 1494 (2010).
[7]. Delimitation of the rice wide compatibility gene S5n to a 40-kb DNA fragment . Theoretical and Applied Genetics, 2005, 111(6): 1080-1086
[8]. A Killer-Protector System Regulates Both Hybrid Sterility and Segregation Distortion in Rice . Science, 2012, 337(6100): 1336-1340

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