title: Differing requirements for RAD51 and DMC1 in meiotic pairing of centromeres and chromosome arms in Arabidopsis thaliana.
abstract: During meiosis homologous chromosomes pair, recombine, and synapse, thus ensuring accurate chromosome segregation and the halving of ploidy necessary for gametogenesis. The processes permitting a chromosome to pair only with its homologue are not fully understood, but successful pairing of homologous chromosomes is tightly linked to recombination. In Arabidopsis thaliana, meiotic prophase of rad51, xrcc3, and rad51C mutants appears normal up to the zygotene/pachytene stage, after which the genome fragments, leading to sterility. To better understand the relationship between recombination and chromosome pairing, we have analysed meiotic chromosome pairing in these and in dmc1 mutant lines. Our data show a differing requirement for these proteins in pairing of centromeric regions and chromosome arms. No homologous pairing of mid-arm or distal regions was observed in rad51, xrcc3, and rad51C mutants. However, homologous centromeres do pair in these mutants and we show that this does depend upon recombination, principally on DMC1. This centromere pairing extends well beyond the heterochromatic centromere region and, surprisingly, does not require XRCC3 and RAD51C. In addition to clarifying and bringing the roles of centromeres in meiotic synapsis to the fore, this analysis thus separates the roles in meiotic synapsis of DMC1 and RAD51 and the meiotic RAD51 paralogs, XRCC3 and RAD51C, with respect to different chromosome domains.
authors.affiliation: Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Da Ines
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Abe
authors.forename: Chantal
authors.initials: C
authors.lastname: Goubely
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Gallego
authors.forename: Charles I
authors.initials: CI
authors.lastname: White
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics*; D002503:Centromere / Q000235:genetics; D023902:Chromosome Pairing / Q000235:genetics*; D020090:Chromosome Segregation; D002875:Chromosomes / Q000235:genetics; D053938:DNA Fragmentation; D022041:Euchromatin / Q000235:genetics; D006570:Heterochromatin; D008540:Meiosis / Q000235:genetics; D050505:Mutant Proteins / Q000235:genetics; D051479:Plant Infertility; D051135:Rad51 Recombinase / Q000235:genetics*; D011938:Rec A Recombinases / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C464449:At5g57450 protein, Arabidopsis; D018797:Cell Cycle Proteins; D022041:Euchromatin; D006570:Heterochromatin; D050505:Mutant Proteins; C513034:ATDMC1 protein, Arabidopsis; C495146:ATRAD51 protein, Arabidopsis; D051135:Rad51 Recombinase; D011938:Rec A Recombinases