title: Arabidopsis PCH2 Mediates Meiotic Chromosome Remodeling and Maturation of Crossovers.
abstract: Meiotic chromosomes are organized into linear looped chromatin arrays by a protein axis localized along the loop-bases. Programmed remodelling of the axis occurs during prophase I of meiosis. Structured illumination microscopy (SIM) has revealed dynamic changes in the chromosome axis in Arabidopsis thaliana and Brassica oleracea. We show that the axis associated protein ASY1 is depleted during zygotene concomitant with synaptonemal complex (SC) formation. Study of an Atpch2 mutant demonstrates this requires the conserved AAA+ ATPase, PCH2, which localizes to the sites of axis remodelling. Loss of PCH2 leads to a failure to deplete ASY1 from the axes and compromizes SC polymerisation. Immunolocalization of recombination proteins in Atpch2 indicates that recombination initiation and CO designation during early prophase I occur normally. Evidence suggests that CO interference is initially functional in the mutant but there is a defect in CO maturation following designation. This leads to a reduction in COs and a failure to form COs between some homologous chromosome pairs leading to univalent chromosomes at metaphase I. Genetic analysis reveals that CO distribution is also affected in some chromosome regions. Together these data indicate that the axis remodelling defect in Atpch2 disrupts normal patterned formation of COs.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lambing
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Kim
authors.initials: K
authors.lastname: Osman
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Komsun
authors.initials: K
authors.lastname: Nuntasoontorn
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Allan
authors.initials: A
authors.lastname: West
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: James D
authors.initials: JD
authors.lastname: Higgins
authors.affiliation: Department of Biology and Carolina Center for Genome Scientists, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Copenhaver
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Armstrong
authors.affiliation: IMP-IMBA, Vienna, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Mechtler
authors.affiliation: IMP-IMBA, Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Roitinger
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: F Chris H
authors.initials: FC
authors.lastname: Franklin
mesh_terms: D000251:Adenosine Triphosphatases / Q000096:biosynthesis / Q000235:genetics*; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000235:genetics*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics*; D032461:Chromosomes, Plant; D003434:Crossing Over, Genetic; D004268:DNA-Binding Proteins / Q000235:genetics*; D008540:Meiosis / Q000235:genetics; D013573:Synaptonemal Complex / Q000235:genetics*
chemical_list: C411742:ASY1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D000251:Adenosine Triphosphatases; C000606549:PCH2 protein, Arabidopsis