The CHD6 chromatin remodeler is an oxidative DNA damage response factor

Abstract

Cell survival after oxidative DNA damage requires signaling, repair and transcriptional events often enabled by nucleosome displacement, exchange or removal by chromatin remodeling enzymes. Here, we show that Chromodomain Helicase DNA-binding protein 6 (CHD6), distinct to other CHD enzymes, is stabilized during oxidative stress via reduced degradation. CHD6 relocates rapidly to DNA damage in a manner dependent upon oxidative lesions and a conserved N-terminal poly(ADP-ribose)-dependent recruitment motif, with later retention requiring the double chromodomain and central core. CHD6 ablation increases reactive oxygen species persistence and impairs anti-oxidant transcriptional responses, leading to elevated DNA breakage and poly(ADP-ribose) induction that cannot be rescued by catalytic or double chromodomain mutants. Despite no overt epigenetic or DNA repair abnormalities, CHD6 loss leads to impaired cell survival after chronic oxidative stress, abnormal chromatin relaxation, amplified DNA damage signaling and checkpoint hypersensitivity. We suggest that CHD6 is a key regulator of the oxidative DNA damage response.

Site-specific targeting of a light activated dCas9-KIllerRed fusion protein generates transient, localized regions of oxidative DNA damage

“…A similar experimental approach was taken by tethering KR to LacR to visualize CHD6 recruitment after oxidative damage (49) and tethering KR to TRF1 to localize oxidative damage to the telomeres (50). These approaches require either expression of engineered, exogenous repeats in the cell (35,49) or loading of the KR-TRF1 fusion onto telomeric repeats (50). This leads to loading of hundreds of copies of the KR construct, generating large regions of oxidative damage.…”

“…Previous studies have established that KR generates reactive oxidative species that directly damage the DNA (35,49,50). KR-induced damage shows overlap with endogenous DNA damage arising from reactive oxygen species (ROS) that naturally occur during cellular metabolism or from exposure to oxidative agents, including oxidized bases, abasic sites, oxypyrimidines, oxypurines, and single strand breaks (12,33,35,(49)(50)(51)(52)(53)(54)(55)(56). Activation of dCas9-KR produced ROS that locally damaged the DNA, resulting in H2AX and KU70/80 spreading at the dCas9 target sequence (Figure 2D, 3D), suggesting that DSBs result after clustered ROS delivery.…”

The Enigmatic Function of PARP1: From PARylation Activity to PAR Readers

“…OB-fold PAR-binding properties have been described for BRCA2 and SSB1 (with the K d 150-170 nM) [70,71]. Recently, KR-rich domains, SR repeats and RG/RGG-rich domains, have been shown to bind PAR, most likely because arginine and/or lysine enrichment are positively charged and bind PAR via electrostatic forces [72,73]. The structures of these domains, their abundance and PAR patterns to interact with, have been well described [69].…”

The Emerging Roles of ATP-Dependent Chromatin Remodeling Complexes in Pancreatic Cancer

“…CHD6 * Chromodomain Helicase DNA Binding Protein 6. A cancer driver and key regulator of the oxidative DNA damage response [211].…”