DNA-PKcs and ATM epistatically suppress DNA end resection and hyperactivation of ATR-dependent G₂-checkpoint in S-phase irradiated cells.

ABSTRACT: We previously reported that cells exposed to low doses of ionizing radiation (IR) in the G₂-phase of the cell cycle activate a checkpoint that is epistatically regulated by ATM and ATR operating as an integrated module. In this module, ATR interphases exclusively with the cell cycle to implement the checkpoint, mainly using CHK1. The ATM/ATR module similarly regulates DNA end-resection at low IR-doses. Strikingly, at high IR-doses, the ATM/ATR coupling relaxes and each kinase exerts independent contributions to resection and the G₂-checkpoint. DNA-PKcs links to the ATM/ATR module and defects cause hyper-resection and hyperactivation of G₂-checkpoint at all doses examined. Surprisingly, our present report reveals that cells irradiated in S-phase utilize a di

SUBMITTER: Mladenov E 

PROVIDER: S-EPMC6787047 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature