The conserved core domain of the human TATA binding protein is sufficient to assemble the multisubunit RNA polymerase I-specific transcription factor SL1.
The human ribosomal RNA polymerase (Pol) I promoter selectivity factor SL1 is a complex consisting of the TATA binding protein (TBP) and three TBP-associated factors (TAFs). We have investigated which elements of TBP are involved in the assembly of Pol I-specific TBP-TAF complexes by comparing SL1 isolated from two human cell lines, one expressing epitope-tagged full-length TBP and another expressing a deletion of nearly the entire N-terminal domain (e delta NTBP). We have immunopurified epitope-tagged full-length TBP- and e delta NTBP-TAF complexes and show that e delta NTBP reconstitutes SL1 activity almost as well as full-length TBP. Moreover, e delta NTBP is shown to be associated with all three Pol I-specific TAFs. Thus, the core of TBP alone is sufficient for the correct assembly of the Pol I-specific TBP-TAF complex, and the variable N-terminal region of human TBP is not required for transcriptional activity. We also demonstrate by an in vitro protein-protein interaction assay that TBP directly interacts with the smallest TAF, TAFI48.
Rudloff
U
U
German Cancer Research Center, Division of Molecular Biology of the Cell II, Heidelberg.
Eberhard
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D
Grummt
I
I
D000595:Amino Acid Sequence; D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism; D002846:Chromatography, Affinity; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D035463:Pol1 Transcription Initiation Complex Proteins; D011499:Protein Processing, Post-Translational; D012318:RNA Polymerase I / Q000378:metabolism*; D017384:Sequence Deletion; D016385:TATA Box; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D035463:Pol1 Transcription Initiation Complex Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; C063660:transcription initiation factor TIF-IB; D012318:RNA Polymerase I