Localized recruitment of a chromatin-remodeling activity by an activator in vivo drives transcriptional elongation.
To understand the role of chromatin-remodeling activities in transcription, it is necessary to understand how they interact with transcriptional activators in vivo to regulate the different steps of transcription. Human heat shock factor 1 (HSF1) stimulates both transcriptional initiation and elongation. We replaced mouse HSF1 in fibroblasts with wild-type and mutant human HSF1 constructs and characterized regulation of an endogenous mouse hsp70 gene. A mutation that diminished transcriptional initiation led to twofold reductions in hsp70 mRNA induction and recruitment of a SWI/SNF remodeling complex. In contrast, a mutation that diminished transcriptional elongation abolished induction of full-length mRNA, SWI/SNF recruitment, and chromatin remodeling, but minimally impaired initiation from the hsp70 promoter. Another remodeling factor, SNF2h, is constitutively present at the promoter irrespective of the genotype of HSF1. These data suggest that localized recruitment of SWI/SNF drives a specialized remodeling reaction necessary for the production of full-length hsp70 mRNA.
Corey
Laura L
LL
Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Weirich
Christine S
CS
Benjamin
Ivor J
IJ
Kingston
Robert E
RE
D000818:Animals; D002460:Cell Line; D002843:Chromatin / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology*; D005786:Gene Expression Regulation / Q000235:genetics*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D000076249:Heat Shock Transcription Factors; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection
D002843:Chromatin; D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors