title: Coactivator and promoter-selective properties of RNA polymerase I TAFs.
abstract: Human ribosomal RNA synthesis by RNA polymerase I requires the activator UBF and the promoter selectivity factor SL1, which consists of the TATA binding protein (TBP) and three associated subunits, TAFI110, TAFI63, and TAFI48. Here it is shown that both TAFI110 and TAFI63 contact the promoter, whereas TAFI48 serves as a target for interaction with UBF and is required to form a transcriptionally active SL1 complex responsive to UBF in vitro. TAFI48 also alters the ability of TBP to interact with TATA box elements, and the resulting complex fails to support transcription by RNA polymerase II. Thus, TAFI48 may function both as a target to mediate UBF activation and as a class-specific promoter selectivity factor.
mesh_terms: D004268:DNA-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D035463:Pol1 Transcription Initiation Complex Proteins; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism; D012335:RNA, Ribosomal / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D016385:TATA Box; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D035463:Pol1 Transcription Initiation Complex Proteins; D012335:RNA, Ribosomal; D011994:Recombinant Proteins; C091131:TAF1A protein, human; C091129:TAF1B protein, human; C486319:TAF1C protein, human; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D014157:Transcription Factors; C063844:transcription factor UBF; C063660:transcription initiation factor TIF-IB; D012319:RNA Polymerase II; D012318:RNA Polymerase I