Os03g0236966
- The rice gene Os03g0236966 was reported as OsAPC6. The candidate gene of 8.6-kb length encodes a 728-amino acid protein containing a conserved tetratricopeptide repeat (TPR) domain and has only a paralog, isopenicillin N-synthase family protein on the same chromosome without the TPR domain[1].
Contents
Annotated Information
Function
- APC/C is an essential E3 ubiquitin–protein ligase that regulates mitotic progression and exit by controlling the stability of cell cycle regulatory proteins, like securin and the mitotic cyclins. OsAPC6 encodes the protein APC6 which is the subunit of large holoenzyme APC/C. The OsAPC6 mutation due to T-DNA insertion in the wild-type gene in Basmati 370 might have led to GA-insensitive dwarf phenotype of OsAPC6 mutant. High sterility in dwarf mutant OsAPC6 may be attributed to loss of function of APC6 subunit causing the holoenzyme nonfunctional which is responsible for mitotic progression from metaphase to anaphase. This may also lead to reduction in cell division and reduced cell number resulting in its dwarf phenotype[1].
Mutation
- The height of OsAPC6 mutant plants (∼80 cm.) and length of different internodes of tillers were reduced to half of that of wild-type Basmati 370 (160 cm; Fig. 1a and b). Nearly, 40–45% seed sterility was observed in the OsAPC6 mutant with grain L/B ratio of 4.8 while in Basmati 370, it was 6.0 (Fig. 1c, d, and e). In the longitudinal section (LS) of the second internode, the length of cells in certain layers was reduced to half to that of the wild-type plants (SI, Fig. S1a and b). While the transverse section (TS; SI, Fig. S1c and d) had enhanced number of cell layers in the dwarf mutant (∼17) as compared to Basmati 370 (∼12). Similarly, in TS (SI, Fig. S1e and f), the number of cells in the leaf xylem was found to be more in the dwarf mutant as compared to Basmati 370. Reduction in cell size of OsAPC6 in the vascular bundles of fourth leaves was also observed in TS[1].
Fig. 1 Comparative morphology of Basmati 370 and OsAPC6.' [1].
- Plant height of OsAPC6 mutant increased only 10% after exogenous gibberellic acid application which was not significantly different from the average plant height without GA3 application. This lack of response to GA3 indicated that the dwarf mutant OsAPC6 is gibberellic acid insensitive while all the cultivars with and without the sd1 dwarfing gene were GA3 sensitive[1].
Table 1 Plant height of different rice cultivars and dwarf mutant OsAPC6 before and after GA3 application at 120 ppm. Common letters on mean values of plant height denotes nonsignificant difference among varieties [1].
Subcellular localization
- In RT-PCR, a fragment of 350 bp was amplified using the cDNA-specific primers (DRTF and DRTR) in both roots and shoots (20 seedlings) of the wild-type Basmati 370, whereas no amplification was observed in the dwarf mutant (Fig. 2). The expression of wild-type gene in Basmati 370 was equal in both roots and shoots in 10-day-old seedlings. Lack of any amplification in the dwarf mutant OsAPC6 indicated the loss of expressions of wild-type gene due to T-DNA insertion[1].
Fig. 2 RT-PCR analyses in the roots and shoots of Basmati 370 and dwarf mutant OsAPC6 using actin as the referencegene. M=100-bp ladder. Lanes 1, 3, 5, and 7, actin; lanes 2 and 6, OsAPC6; Lanes 4 and 8, Basmati 370 [1].
Labs working on this gene
- National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, Pusa Campus, New Delhi 110012, India
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Kumar M, Basha PO, Puri A, Rajpurohit D, Randhawa GS, Sharma TR, Dhaliwal HS. A candidate gene OsAPC6 of anaphase-promoting complex of rice identified through T-DNA insertion. Funct Integr Genomics. 2010 Aug;10(3):349-58. doi: 10.1007/s10142-009-0155-6. Epub 2010 Jan 21. PubMed PMID: 20091079.
