摘要Objective:To investigate the impact of SWI/SNF complex on heterochromatin DNA damage repair after exposure to X-ray irradiation,in order to explore the underlying mechanism.Methods:NIH3T3 and MRC5 cells were treated with 50 nmol/L siRNA targeting SWI/SNF complex subunits(BRM,ARID1A,BRG1 and SNF5),and YAP/TAZ.At 24 h after transfection,the cells were irradiated with 0.5 and 1 Gy of X-rays.At 20,60 and 240 min post-irradiation,γH2AX assay was performed to evaluate the radiation response in total or heterochromatin.Comet assay was used to determine the role of YAP/TAZ in DNA damage when the cells were irradiated with 4 Gy of X-rays.NIH3T3 were treated with 50 nmol/L siRNA targeting BRM/BRG1 and YAP/TAZ to determine their relationship on heterochromatin DNA damage repair.Results:In NIH3T3,SWI/SNF complex subunits(BRM,ARID 1A and BRG1)knock-down increased γH2AX in total and heterochromatin at 1 Gy 60 min post-irradiation(P＜0.05),while SNF5 knock-down decreased hetero-chromatin γH2AX at 1 Gy 20 min post-irradiation(P＜0.05).In MRC5,BRM and BRG1 knock-down increasedγH2AX in total and heterochromatin at 1 Gy 60 min post-irradiation(P＜0.05).Inconsistently,ARID1A knock-down did not affect it,and SNF5 knock-down increased heterochromatin γH2AX at 1 Gy 60 min post-irradiation(P＜0.05).Moreover,YAP/TAZ knock-down decreased heterochromatin γH2AX in NIH3T3 and MRC5(P＜0.05).Meanwhile,YAP/TAZ knock-down decreased Tail Moment in comet assay at 4 Gy 60 min post-irradiation(P＜0.05).BRM/BRG1 combining with YAP/TAZ knock-down significantly decreased heterochromatin γH2AX compared with single BRM/BRG1 knock-down at 0.5 Gy 60 min post-irradiation(P＜0.05).Conclusions:The SWI/SNF complex subunits exhibited varying effects on DNA damage repair.BRM/BRG1 knock-down promoted γH2AX accumulation in heterochromatin through YAP/TAZ.This study provides a novel direc-tion for DNA damage repair and sheds light on the role of SWI/SNF complex in response to DNA damage repair in heterochromatin.