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PLoS Biol. 2016 Feb 12;14(2):e1002369. doi: 10.1371/journal.pbio.1002369. eCollection 2016 Feb.

Chromosome Synapsis Alleviates Mek1-Dependent Suppression of Meiotic DNA Repair.

Author information

1
Department of Biology, New York University, New York, New York, United States of America.
2
Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, Connecticut, United States of America.
3
Institute for Protein Research, Osaka University, Suita, Osaka, Japan.
4
Institut Curie/Centre de Recherche, CNRS, UMR3664, Paris, France.

Abstract

Faithful meiotic chromosome segregation and fertility require meiotic recombination between homologous chromosomes rather than the equally available sister chromatid, a bias that in Saccharomyces cerevisiae depends on the meiotic kinase, Mek1. Mek1 is thought to mediate repair template bias by specifically suppressing sister-directed repair. Instead, we found that when Mek1 persists on closely paired (synapsed) homologues, DNA repair is severely delayed, suggesting that Mek1 suppresses any proximal repair template. Accordingly, Mek1 is excluded from synapsed homologues in wild-type cells. Exclusion requires the AAA+-ATPase Pch2 and is directly coupled to synaptonemal complex assembly. Stage-specific depletion experiments further demonstrate that DNA repair in the context of synapsed homologues requires Rad54, a repair factor inhibited by Mek1. These data indicate that the sister template is distinguished from the homologue primarily by its closer proximity to inhibitory Mek1 activity. We propose that once pairing or synapsis juxtaposes homologues, exclusion of Mek1 is necessary to avoid suppression of all templates and accelerate repair progression.

PMID:
26870961
PMCID:
PMC4752329
DOI:
10.1371/journal.pbio.1002369
[Indexed for MEDLINE]
Free PMC Article

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