title: MRE11 is required for homologous synapsis and DSB processing in rice meiosis.
abstract: Mre11, a conserved protein found in organisms ranging from yeast to multicellular organisms, is required for normal meiotic recombination. Mre11 interacts with Rad50 and Nbs1/Xrs2 to form a complex (MRN/X) that participates in double-strand break (DSB) ends processing. In this study, we silenced the MRE11 gene in rice and detailed its function using molecular and cytological methods. The OsMRE11-deficient plants exhibited normal vegetative growth but could not set seed. Cytological analysis indicated that in the OsMRE11-deficient plants, homologous pairing was totally inhibited, and the chromosomes were completely entangled as a formation of multivalents at metaphase I, leading to the consequence of serious chromosome fragmentation during anaphase I. Immunofluorescence studies further demonstrated that OsMRE11 is required for homologous synapsis and DSB processing but is dispensable for meiotic DSB formation. We found that OsMRE11 protein was located on meiotic chromosomes from interphase to late pachytene. This protein showed normal localization in zep1, Oscom1 and Osmer3, as well as in OsSPO11-1(RNAi) plants, but not in pair2 and pair3 mutants. Taken together, our results provide evidence that OsMRE11 performs a function essential for maintaining the normal HR process and inhibiting non-homologous recombination during 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: Mo
authors.initials: M
authors.lastname: Wang
authors.forename: Yafei
authors.initials: Y
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Kejian
authors.initials: K
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D023902:Chromosome Pairing / Q000235:genetics; D053903:DNA Breaks, Double-Stranded; D018506:Gene Expression Regulation, Plant; D059765:Homologous Recombination / Q000235:genetics; D008540:Meiosis / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D013573:Synaptonemal Complex / Q000235:genetics
chemical_list: D010940:Plant Proteins