Accurate positioning of RNA polymerase II on a natural TATA-less promoter is independent of TATA-binding-protein-associated factors and initiator-binding proteins.
Two promoter elements, the TATA element and initiator (Inr), are capable of directing specific transcription initiation of protein-encoding genes by RNA polymerase II (RNAPII). Although binding to the TATA element by the TATA-binding protein (TBP) has been shown to be the initial recognition step in transcription complex formation in vitro, the mechanism through which the basal machinery assembles into a functional complex on TATA-less promoters is controversial. Evidence supporting numerous models of Inr-mediated transcription complex formation exists, including the nucleation of a complex by Inr-binding proteins, a component of the TFIID complex, or a specific upstream activator common to many TATA-less promoters, Sp1. Using various techniques, we have undertaken a systematic analysis of the natural TATA-less human DNA polymerase beta (beta-pol) gene promoter. Although the beta-pol promoter contains upstream Sp1 elements and a functional Inr that binds YY1, neither of these factors is essential for Inr-mediated transcription complex formation. A complex containing TBP, TFIIB, TFIIF, and RNAPII (DBPolF complex) is capable of forming on the promoter in an Inr-dependent manner. A single point mutation within the Inr that affects DBPolF complex formation diminishes beta-pol transcriptional activity.
Weis
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Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635, USA.
Reinberg
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D001665:Binding Sites; D004256:DNA Polymerase I / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D016385:TATA Box; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000378:metabolism; D014158:Transcription, Genetic; D050986:YY1 Transcription Factor; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; D012319:RNA Polymerase II; D004256:DNA Polymerase I; C056604:transcription factor TFIIF