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akirin is required for diakinesis bivalent structure and synaptonemal complex disassembly at meiotic prophase I
Journal article   Open access   Peer reviewed

akirin is required for diakinesis bivalent structure and synaptonemal complex disassembly at meiotic prophase I

Amy M Clemons, Heather M Brockway, Yizhi Yin, Bhavatharini Kasinathan, Yaron S Butterfield, Steven J M Jones, Monica P Colaiácovo and Sarit Smolikove
Molecular biology of the cell, Vol.24(7), pp.1053-1067
04/2013
DOI: 10.1091/mbc.E12-11-0841
PMCID: PMC3608493
PMID: 23363597
url
https://doi.org/10.1091/mbc.E12-11-0841View
Published (Version of record) Open Access

Abstract

During meiosis, evolutionarily conserved mechanisms regulate chromosome remodeling, leading to the formation of a tight bivalent structure. This bivalent, a linked pair of homologous chromosomes, is essential for proper chromosome segregation in meiosis. The formation of a tight bivalent involves chromosome condensation and restructuring around the crossover. The synaptonemal complex (SC), which mediates homologous chromosome association before crossover formation, disassembles concurrently with increased condensation during bivalent remodeling. Both chromosome condensation and SC disassembly are likely critical steps in acquiring functional bivalent structure. The mechanisms controlling SC disassembly, however, remain unclear. Here we identify akir-1 as a gene involved in key events of meiotic prophase I in Caenorhabditis elegans. AKIR-1 is a protein conserved among metazoans that lacks any previously known function in meiosis. We show that akir-1 mutants exhibit severe meiotic defects in late prophase I, including improper disassembly of the SC and aberrant chromosome condensation, independently of the condensin complexes. These late-prophase defects then lead to aberrant reconfiguring of the bivalent. The meiotic divisions are delayed in akir-1 mutants and are accompanied by lagging chromosomes. Our analysis therefore provides evidence for an important role of proper SC disassembly in configuring a functional bivalent structure.
 Caenorhabditis elegans Proteins - metabolism Male Time-Lapse Imaging Oocytes - cytology RNA Interference Chromosomes - genetics Meiotic Prophase I Cell Cycle Proteins - genetics Chromosomes - metabolism Female Nuclear Proteins - genetics Rad51 Recombinase - metabolism Caenorhabditis elegans - metabolism Crossing Over, Genetic Chromosomal Proteins, Non-Histone - metabolism Rad51 Recombinase - genetics Caenorhabditis elegans - genetics Oocytes - metabolism Cell Cycle Proteins - metabolism In Situ Hybridization, Fluorescence Nuclear Proteins - metabolism Chromosomal Proteins, Non-Histone - genetics Synaptonemal Complex - metabolism Animals Alleles Luminescent Proteins - genetics Mutation Caenorhabditis elegans Proteins - genetics Chromosome Pairing Microscopy, Fluorescence Luminescent Proteins - metabolism

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