title: TAC, a TBP-sans-TAFs complex containing the unprocessed TFIIAalphabeta precursor and the TFIIAgamma subunit.
abstract: Transcription of TATA box-containing genes by RNA polymerase II is mediated by TBP-containing and TBP-free multisubunit complexes consisting of common and unique components. We have identified a highly stable TBP-TFIIA-containing complex, TAC, which is detectable in embryonal carcinoma (EC) cells but not in differentiated cells. TAC contains the TFIIAgamma subunit and the unprocessed form of TFIIAalphabeta, although the processed TFIIAalpha and TFIIAbeta subunits are present in EC cells. TAC mediates transcriptional activation by RNA polymerase II in vivo, even though it does not contain classical TAFs. Formaldehyde cross-linking revealed that in EC but not in differentiated cells, association of TBP with chromatin is strongly enhanced when complexed with TFIIA in vivo. Remarkably, the TFIIAalphabeta precursor is preferentially, if not exclusively, associated with chromatin as compared to the processed subunits present in "free" TFIIA in EC cells.
authors.affiliation: Department of Molecular Biology, University of Nijmegen, The Netherlands.
authors.forename: D J
authors.initials: DJ
authors.lastname: Mitsiou
authors.forename: H G
authors.initials: HG
authors.lastname: Stunnenberg
mesh_terms: D000818:Animals; D019556:COS Cells; D018236:Carcinoma, Embryonal; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D003432:Cross-Linking Reagents; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005557:Formaldehyde; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D016385:TATA Box / Q000502:physiology; D035181:TATA-Box Binding Protein; D035561:Transcription Factor TFIIA; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D002843:Chromatin; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D011498:Protein Precursors; D035181:TATA-Box Binding Protein; D035561:Transcription Factor TFIIA; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D005557:Formaldehyde; D004247:DNA