Faithful chromosome segregation into gametes depends on Spo11-induced DNA double-strand breaks (DSBs). These yield single-stranded 30 tails upon resection to promote crossovers (COs). While early Mre11-dependent end resection is the predominant pathway in most organisms, Exo1 or Dna2/BLM can also contribute to the efficient processing of meiotic DSBs. Although its enzymatic activity has been thor-oughly dissected, the temporal dynamics underlying Spo11 activity have remained mostly elusive. We show that, in Caenorhabditis elegans, SPO-11-mediated DSB induction takes place throughout early meiotic prophase I until mid-late pachynema. We find that late DSBs are essential for CO formation and are prefer-entially processed by EXO-1 and DNA-2 in a redundant fashion. Further, EXO-1-DNA-2-mediated resection ensures completion of conservative DSB repair and discourages activation of KU-dependent end joining. Taken together, our data unveil important temporal aspects of DSB induction and identify previously un-known functional implications for EXO-1-DNA-2-mediated resection activity in C. elegans.
Návaznosti
GA20-08819S, projekt VaV
Název: Pochopení úlohy PARG při podpoře tvorby a oprav dvouřetězcových zlomů DNA v meióze
Investor: Grantová agentura ČR, Pochopení úlohy PARG při podpoře tvorby a oprav dvouřetězcových zlomů DNA v meióze
LM2018129, projekt VaV
Název: Národní infrastruktura pro biologické a medicínské zobrazování Czech-BioImaging
Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, National research infrastructure for biological and medical imaging