Switch defective/sucrose non-fermentable(SWI/SNF)chromatin remodeling complexes are multi-subunit machines that play vital roles in the regulation of chromatin structure and gene expression.However,the mechanisms by w...Switch defective/sucrose non-fermentable(SWI/SNF)chromatin remodeling complexes are multi-subunit machines that play vital roles in the regulation of chromatin structure and gene expression.However,the mechanisms by which SWI/SNF complexes recognize their target loci in plants are not fully understood.Here,we show that the Arabidopsis thaliana bromodomain-containing proteins BRD1,BRD2,and BRD13 are core subunits of SWI/SNF complexes and critical for SWI/SNF genomic targeting.These three BRDs interact directly with multiple SWI/SNF subunits,including the BRAHMA(BRM)catalytic subunit.Phenotypic and transcriptomic analyses of the brd1 brd2 brd13 triple mutant revealed that these BRDs act largely redundantly to control gene expression and developmental processes that are also regulated by BRM.Genome-wide occupancy profiling demonstrated that these three BRDs extensively colocalize with BRM on chromatin.Simultaneous loss of function of three BRD genes results in reduced BRM protein levels and decreased occupancy of BRM on chromatin across the genome.Furthermore,we demonstrated that the bromodomains of BRDs are essential for genomic targeting of the BRD subunits of SWI/SNF complexes to their target sites.Collectively,these results demonstrate that BRD1,BRD2,and BRD13 are core subunits of SWI/SNF complexes and reveal their biological roles in facilitating genomic targeting of BRM-containing SWI/SNF complexes in plants.展开更多
SWI/SNF chromatin remodelers are evolutionarily conserved multiprotein complexes that use the energy of ATP hydrolysis to change chromatin structure.A characteristic feature of SWI/SNF remodelers is the occurrence in ...SWI/SNF chromatin remodelers are evolutionarily conserved multiprotein complexes that use the energy of ATP hydrolysis to change chromatin structure.A characteristic feature of SWI/SNF remodelers is the occurrence in both the catalytic ATPase subunit and some auxiliary subunits,of bromodomains,the protein motifs capable of binding acetylated histones.Here,we report that the Arabidopsis bromodomaincontaining proteins BRD1,BRD2,and BRD13 are likely true SWI/SNF subunits that interact with the core SWI/SNF components SWI3C and SWP73B.Loss of function of each single BRD protein caused early flowering but had a negligible effect on other developmental pathways.By contrast,a brd triple mutation(brdx3)led to more pronounced developmental abnormalities,indicating functional redundancy among the BRD proteins.The brdx3 phenotypes,including hypersensitivity to abscisic acid and the gibberellin biosynthesis inhibitor paclobutrazol,resembled those of swi/snf mutants.Furthermore,the BRM protein level and occupancy at the direct target loci SCL3,ABI5,and SVP were reduced in the brdx3 mutant background.Finally,a brdx3 brm-3 quadruple mutant,in which SWI/SNF complexes were devoid of all constituent bromodomains,phenocopied a loss-of-function mutation in BRM.Taken together,our results demonstrate the relevance of BRDs as SWI/SNF subunits and suggest their cooperation with the bromodomain of BRM ATPase.展开更多
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 w...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,ARID1A and BRG1)knock-down increasedγH2AX in total and heterochromatin at 1 Gy 60 min post-irradiation(P<0.05),while SNF5 knock-down decreased heterochromatinγH2AX 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 knockdown did not affect it,and SNF5 knock-down increased heterochromatinγH2AX at 1 Gy 60 min post-irradiation(P<0.05).Moreover,YAP/TAZ knock-down decreased heterochromatinγH2AX 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 heterochromatinγH2AX 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 knockdown promotedγH2AX accumulation in heterochromatin through YAP/TAZ.This study provides a novel direction for DNA damage repair and sheds light on the role of SWI/SNF complex in response to DNA damage repair in heterochromatin.展开更多
基金supported by the National Natural Science Foundation of China to C.L.(32000380 and 31870289)Guangdong Basic and Applied Basic Research Foundation to C.L.(2021A1515011286)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University to C.L(18lgzd12).
文摘Switch defective/sucrose non-fermentable(SWI/SNF)chromatin remodeling complexes are multi-subunit machines that play vital roles in the regulation of chromatin structure and gene expression.However,the mechanisms by which SWI/SNF complexes recognize their target loci in plants are not fully understood.Here,we show that the Arabidopsis thaliana bromodomain-containing proteins BRD1,BRD2,and BRD13 are core subunits of SWI/SNF complexes and critical for SWI/SNF genomic targeting.These three BRDs interact directly with multiple SWI/SNF subunits,including the BRAHMA(BRM)catalytic subunit.Phenotypic and transcriptomic analyses of the brd1 brd2 brd13 triple mutant revealed that these BRDs act largely redundantly to control gene expression and developmental processes that are also regulated by BRM.Genome-wide occupancy profiling demonstrated that these three BRDs extensively colocalize with BRM on chromatin.Simultaneous loss of function of three BRD genes results in reduced BRM protein levels and decreased occupancy of BRM on chromatin across the genome.Furthermore,we demonstrated that the bromodomains of BRDs are essential for genomic targeting of the BRD subunits of SWI/SNF complexes to their target sites.Collectively,these results demonstrate that BRD1,BRD2,and BRD13 are core subunits of SWI/SNF complexes and reveal their biological roles in facilitating genomic targeting of BRM-containing SWI/SNF complexes in plants.
基金supported by grants from National Science Centre project nos.2014/15/N/NZ2/00396 to K.J.,2014/13/B/NZ1/00967 to A.J.,and 2017/26/E/NZ2/00899 to R.A.sponsored in part by the Center for Preclinical Research and Technology(CePT)+1 种基金a project co-sponsored by the European Regional Development Fund and Innovative EconomyThe National Cohesion Strategy of Poland.
文摘SWI/SNF chromatin remodelers are evolutionarily conserved multiprotein complexes that use the energy of ATP hydrolysis to change chromatin structure.A characteristic feature of SWI/SNF remodelers is the occurrence in both the catalytic ATPase subunit and some auxiliary subunits,of bromodomains,the protein motifs capable of binding acetylated histones.Here,we report that the Arabidopsis bromodomaincontaining proteins BRD1,BRD2,and BRD13 are likely true SWI/SNF subunits that interact with the core SWI/SNF components SWI3C and SWP73B.Loss of function of each single BRD protein caused early flowering but had a negligible effect on other developmental pathways.By contrast,a brd triple mutation(brdx3)led to more pronounced developmental abnormalities,indicating functional redundancy among the BRD proteins.The brdx3 phenotypes,including hypersensitivity to abscisic acid and the gibberellin biosynthesis inhibitor paclobutrazol,resembled those of swi/snf mutants.Furthermore,the BRM protein level and occupancy at the direct target loci SCL3,ABI5,and SVP were reduced in the brdx3 mutant background.Finally,a brdx3 brm-3 quadruple mutant,in which SWI/SNF complexes were devoid of all constituent bromodomains,phenocopied a loss-of-function mutation in BRM.Taken together,our results demonstrate the relevance of BRDs as SWI/SNF subunits and suggest their cooperation with the bromodomain of BRM ATPase.
基金supported by grants from National Natural Science Foundation of China(31971165 and 82173465)Leading Talents Program of Gusu District(ZXL2022454)Jiangsu Provincial Outstanding Postdoctoral Program(2023ZB254),China.
文摘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,ARID1A and BRG1)knock-down increasedγH2AX in total and heterochromatin at 1 Gy 60 min post-irradiation(P<0.05),while SNF5 knock-down decreased heterochromatinγH2AX 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 knockdown did not affect it,and SNF5 knock-down increased heterochromatinγH2AX at 1 Gy 60 min post-irradiation(P<0.05).Moreover,YAP/TAZ knock-down decreased heterochromatinγH2AX 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 heterochromatinγH2AX 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 knockdown promotedγH2AX accumulation in heterochromatin through YAP/TAZ.This study provides a novel direction for DNA damage repair and sheds light on the role of SWI/SNF complex in response to DNA damage repair in heterochromatin.
