Arabidopsis PCH2 Mediates Meiotic Chromosome Remodeling and Maturation of Crossovers

• DOI: 10.1371/journal.pgen.1005372
• Publication Date: 2015-07-16T17:55:14Z
• Authors: Christophe Lambing; Kim Osman; Komsun Nuntasoontorn; Allan West; James D. Higgins; Gregory P. Copenh...; Jianhua Yang; Susan J. Armstrong; Karl Mechtler; Elisabeth Roitinger; F. Chris H. Franklin
• Keywords: Synaptonemal complex

Meiotic chromosomes are organized into linear looped chromatin arrays by a protein axis localized along the loop-bases. Programmed remodelling of occurs during prophase I meiosis. Structured illumination microscopy (SIM) has revealed dynamic changes in chromosome Arabidopsis thaliana and Brassica oleracea. We show that associated ASY1 is depleted zygotene concomitant with synaptonemal complex (SC) formation. Study an Atpch2 mutant demonstrates this requires conserved AAA+ ATPase, PCH2, which localizes to sites remodelling. Loss PCH2 leads failure deplete from axes compromizes SC polymerisation. Immunolocalization recombination proteins indicates initiation CO designation early occur normally. Evidence suggests interference initially functional but there defect maturation following designation. This reduction COs form between some homologous pairs leading univalent at metaphase I. Genetic analysis reveals distribution also affected regions. Together these data indicate disrupts normal patterned formation COs.