OGT Mediated Histone H2B S112GlcNAc Regulates DNA Damage Response

Histone modifications play important roles not only in chromatin structure remodeling,but also in determining cell fate,cell growth and the process of carcinogenesis.O-GlcNAcylation,regulated by O-GlcNAc transferase(OGT)and O-GlcNAcase(OGA),is an important posttranslational modification,which regulates the activities of a wide panel of proteins.Studies have shown that phosphorylation and O-GlcNAcylation exist extensive crosstalk and OGT can affect phosphorylation on proteins involved in DNA damage response,but whether OGT directly taking part in DDR is still unclear.Moreover,recent studies shown OGT mediated histone GlcNAcylation plays an important role in gene transcription.However,the role of this histone modification in DNA damage response has not been studied yet.In this shudy,we investigated the function of OGT and OGT mediated H2B S112GlcNAc in DNA repair response and its underlying mechanism.Using analysis of sensitiviy to DNA damaging agents,immunofluorescence and DNA damage repair assay,we found depletion of OGT or overexpression of H2B S112A mutant resulted in hypersensitiviy to DNA damaging agents,prolonged yH2AX foci and impaired HR and NHEJ.In addition,using ChIP assay,we also found H2B S112GlcNAc increased locally upon the induction of DSBs.These results showe that OGT and OGT mediated H2B S112GlcNAc directly take part in DNA damage repair.To exploring the mechanism,we made use of mass spectrometry analysis and found that H2B S112GlcNAc can interact with NBS1 and this interaction had been verified by Immunoprecipitation.Moreover,using immunofluorescence,we also found H2B S112 GlcNAc could regulate NBS1 foci formation.Taken together,our results demonstrate OGT directly take part in DNA damae repair and H2B S11GlcNAc regulates DNA damage response by interacting with NSB1 and regulating its accumulation at DSB sites.