Inter-Homolog Crossing-Over and Synapsis in Arabidopsis Meiosis Are Dependent on the Chromosome Axis Protein AtASY3

• DOI: 10.1371/journal.pgen.1002507
• Publication Date: 2012-02-02T21:43:41Z
• Authors: Maheen Ferdous; James D. Higgins; Kim Osman; Christophe Lambing; Elisabeth Roitinger; Karl Mechtler; Susan J. Armstrong; Ruth Perry; Mónica Pradillo; Nieves Cuñado; F. Chris H. Franklin
• Keywords: Synaptonemal complex; Synapsis; Meiocyte

In this study we have analysed AtASY3, a coiled-coil domain protein that is required for normal meiosis in Arabidopsis. Analysis of an Atasy3-1 mutant reveals loss the compromises chromosome axis formation and results reduced numbers meiotic crossovers (COs). Although frequency DNA double-strand breaks (DSBs) appears moderately Atasy3-1, main recombination defect reduction COs. Immunolocalization studies wild-type meiocytes indicate HORMA AtASY1, which related to Hop1 budding yeast, forms hyper-abundant domains along chromosomes are spatially associated with DSBs early pathway proteins. Loss AtASY3 disrupts axial organization AtASY1. Furthermore show AtASY1 homologs BoASY3 BoASY1, from closely species Brassica oleracea, co-immunoprecipitated meiocyte extracts interacts via residues its predicted domain. Together our suggest functional homolog Red1. Since yeast Red1 play key role establishing bias favor inter-homolog (IHR), propose may similar also synaptonemal complex (SC) formation. transverse filament AtZYP1 small patches rather than continuous SC. The few AtMLH1 foci remain found association patches. This sufficient prevent ectopic observed absence AtZYP1, thus emphasizing addition structural important CO