Chromatin profiling of DNA damage response proteins reveals a role of RNF169 in single strand annealing repair

Abstract

Spatial distribution of DNA damage response (DDR) machineries at the damaged chromatin provides important clues to probe their roles in DNA double strand break (DSB) responses. The Ring Finger protein169 (RNF169) fine-tunes the threshold and magnitude of DSB responses by impeding the access of key DNA damage mediator protein 53BP1 onto the damaged chromatin. However, exactly how the antagonism of RNF169 and 53BP1 at DSBs contributes to DNA repair remains undefined. In this study, we uncovered a role of the RNF169 and 53BP1 interplay in controlling single strand annealing (SSA) repair. Specifically, using a sequence-specific DSB-inducible setup, we established that RNF169 and 53BP1 exhibited distinct distribution signatures at DSB-flanking chromatin domains. We further show that RNF169 counteracts 53BP1 deposition and stimulates SSA repair in dose-dependent manners. Together, our preliminary findings implicate the dynamic balance of RNF169 and 53BP1 in restricting erroneous DNA repair, and provide clues to define the functional importance of RNF169 and other negative regulators of DSB responses in the maintenance of genome stability.