Structure-function analysis of the TBP-binding protein Dr1 reveals a mechanism for repression of class II gene transcription.
Dr1, a repressor of class II genes, regulates transcription by a novel mechanism. Biochemical analyses reveal that Dr1 directly interacts with the multiprotein TFIID complex. By use of the yeast two-hybrid system, we demonstrate that the association of Dr1 with the TATA-binding protein (TBP) subunit of TFIID occurs in vivo. In addition, Dr1 can repress transcription from TATA-containing as well as TATA-less promoters in transient transfection assays. Importantly, Dr1-mediated repression can be reversed by overexpression of TBP in vivo. By use of diverse approaches, we mapped two distinct domains in Dr1 required for repression. One domain is essential for the Dr1-TBP interaction, and the second is rich in alanine residues. The TBP-binding domain of Dr1 cannot be replaced by a heterologous DNA-binding domain in mediating repression. We demonstrate that some, but not all, transcriptional activators can reverse Dr1-mediated repression in vivo.
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635.
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Yeung
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Inostroza
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Mermelstein
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Kannabiran
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Reinberg
D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016385:TATA Box; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D017931:DNA Primers; D010750:Phosphoproteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C075995:down-regulator of transcription 1