DNA repair choice defines a common pathway for recruitment of chromatin regulators

Abstract

DNA double‐strand break (DSB) repair is essential for maintenance of genome stability. Recent work has implicated a host of chromatin regulators in the DNA damage response, but their functional roles remain unclear. In budding yeast, DSB recruitment of chromatin regulators has been monitored primarily in asynchronous cell populations, and thus it is unclear if these events are linked to non‐homologous end joining (NHEJ) or homologous recombination (HR). By using synchronized cell populations, we surprisingly find that subunits of the INO80, SWR‐C, NuA4, SWI/SNF, and RSC enzymes, as monitored by chromatin immunoprecipitation (ChIP), are primarily recruited outside of the G1 cell phase. Furthermore, recruitment is inhibited by the NHEJ machinery, and requires early steps of HR, strongly supporting a role for these enzymes in the HR repair pathway. Strikingly, and in contrast to previous reports, we also find no significant role for H2A.X phosphorylation (γH2AX) in the recruitment of chromatin regulators, but rather their recruitment coincides with reduced levels of γH2AX.This work was supported by a grant from the NIH (GM54096).