Chk2 homolog Mek1 limits exonuclease 1–dependent DNA end resection during meiotic recombination in Saccharomyces cerevisiae

Abstract

Abstract The conserved Rad2/XPG family 5′–3′ exonuclease, exonuclease 1 (Exo1), plays many roles in DNA metabolism including during resolution of DNA double-strand breaks via homologous recombination. Prior studies provided evidence that the end resection activity of Exo1 is downregulated in yeast and mammals by Cdk1/2 family cyclin-dependent and checkpoint kinases, including budding yeast kinase Rad53 which functions in mitotic cells. Here, we provide evidence that the master meiotic kinase Mek1, a paralog of Rad53, limits 5′–3′ single-strand resection at the sites of programmed meiotic DNA breaks. Mutational analysis suggests that the mechanism of Exo1 suppression by Mek1 differs from that of Rad53.