title: The role of OsCOM1 in homologous chromosome synapsis and recombination in rice meiosis.
abstract: COM1/SAE2 is a highly conserved gene from yeast to higher eukaryotes. Its orthologs, known to cooperate with the MRX complex (Mre11/Rad50/Xrs2), are required for meiotic DNA double-strand break (DSB) ends resection and specific mitotic DSB repair events. Here, the rice (Oryza sativa, 2n = 2x = 24) COM1/SAE2 homolog was identified through positional cloning, termed OsCOM1. Four independent mutants of OsCOM1 were isolated and characterized. In Oscom1 mutants, synaptonemal complex (SC) formation, homologous pairing and recombination were severely inhibited, whereas aberrant non-homologous chromosome entanglements occurred constantly. Several key meiotic proteins, including ZEP1 and OsMER3, were not loaded normally onto chromosomes in Oscom1 mutants, whereas the localization of OsREC8, PAIR2 and PAIR3 seemed to be normal. Moreover, OsCOM1 was loaded normally onto meiotic chromosomes in Osrec8, zep1 and Osmer3 mutants, but could not be properly loaded in Osam1, pair2 and OsSPO11-1(RNAi) plants. These results provide direct evidence for the functions of OsCOM1 in promoting homologous synapsis and recombination in rice meiosis.
authors.affiliation: State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Ji
authors.forename: Ding
authors.initials: D
authors.lastname: Tang
authors.forename: Kejian
authors.initials: K
authors.lastname: Wang
authors.forename: Mo
authors.initials: M
authors.lastname: Wang
authors.forename: Lixiao
authors.initials: L
authors.lastname: Che
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D000818:Animals; D023902:Chromosome Pairing / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D059765:Homologous Recombination; D056626:Inflorescence / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D018749:RNA, Plant / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics*; D013573:Synaptonemal Complex / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D018749:RNA, Plant