Os05g0498300

OsMSH5,similar to MSH5--a meiosis-specific member of the MutS-homolog family, is required for normal level of recombination.

Annotated Information

Function

1.MSH5, a meiosis-specific member of the MutS-homolog family, is required for normal level of recombination in budding yeast, mice, Caenorhabditis elegans, and Arabidopsis. OsMSH5, is its rice homolog.

2.OsMSH5 functions upstream of OsZIP4, OsMER3, and HEI10 in class I crossover formation.

3.We investigated OsMSH5’s roles during CO formation and synapsis and find that loss of OsMSH5 function resulted in a severe reduction in CO formation, which means OsMSH5, similar to its homolog MSH5, plays a vital role in Meiosis.

4.In addition to ZEP1, three other ZMM proteins including OsZIP4, OsMER3, and HEI10, their loading depends on OsMSH5.

Expression

1.OsMSH5is predominantly expressed in panicles. Immunofluorescence studies indicate that OsMSH5 chromosomal localization is limited to the early meiotic prophase I. In wild-type, OsMSH5 foci appeared almost at the same time as OsREC8 signals at leptotene(Figure 4A). number of OsMSH5 foci accumulated rapidly and reached a peak at early zygotene (Figure 4B). At early pachytene, most OsMSH5 foci started to leave from chromosomes (Figure 4C). With the progression of meiosis, however, the number of OsMSH5 foci decreased rapidly and only a few residual foci were observed at late pachytene. OsMSH5 signals were absent at diplotene and could not be detected thereafter.

Evolution

OsMSH5 shows significant homology with MSH5 in Arabidopsis (66% identity and 82% similarity) and is also highly related to the MSH5 in mammals and budding yeast. OsMSH5 contains a conserved ATP-binding motif at its C-terminus (amino acids: 538–746, conserved domains ), and is similar to AtMSH5 lacking the MutS domain I, which is essential for the activity of DNA mismatch repairing.

Mutation

1.Five independent Osmsh5 mutants exhibited normal vegetative growth and severe sterility. The synaptonemal complex is well installed in Osmsh5, while the chiasma frequency is greatly reduced to approximately 10% of that observed in the wild-type, leading to the homologous nondisjunction and complete sterile phenotype.

2.Five mutants related to MSH5 are designated Osmsh5-1, Osmsh5-2, Osmsh5-3, Osmsh5-4, and Osmsh5-5, respectively. And Osmsh5-1 has single nucleotide T deletion was identified at position 9909, creating a new stop codon in exon 29, displayed a reduction in fertility. Here is the rice Osmsh5-1 mutant phenotype compared with WT phenotype.(figure A and B; figure C and D)

3.In the Osmsh5-1 mutant, meiotic chromosome behavior was almost identical to that of the wild-type from leptotene to pachytene (Figure 3Jand L). However, several chromosomal defects were apparent from diakinesis through to the following meiotic stages. Different numbers of univalents were observed at diakinesis in Osmsh5-1(Figure 3M)

Labs working on this gene

1.College of Plant Protection, Yunnan Agricultural University.

2.bState Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences.

References

1.Qiong Luo, Ding Tang, Mo Wang et al(2013). The Role of OsMSH5 in Crossover Formation during Rice Meiosis, Molecular Plant, 6(3) :729–742.

2.Chelysheva L., Vezon D., Chambon A., Gendrot G., Pereira L., Lemhemdi A., Vrielynck N., Le Guin S., Novatchkova M., Grelon M. (2012). The Arabidopsis HEI10 is a new ZMM protein related to Zip3. PLoS Genet. 8, e1002799