Eukaryotic RNA polymerase I promoter binding is directed by protein contacts with transcription initiation factor and is DNA sequence-independent.
RNA polymerase I binding to the eukaryotic ribosomal RNA gene promoter-transcription initiation factor (TIF) complex was examined by in vitro transcription and footprinting of a series of spacer mutants. Polymerase binds efficiently to the TIF-promoter complex independently of the DNA sequence in the polymerase interaction region and initiates transcription a fixed distance downstream of the TIF binding site on AT-rich templates. Methidiumpropyl-EDTA.FE(II) footprinting confirms minimal contacts between polymerase and DNA. We infer that polymerase is directed to the promoter by a DNA sequence-independent mechanism, solely by protein-protein contacts with TIF. An initiation step subsequent to binding requires special sequence characteristics in the transcription start site region.
D000656:Amoeba / Q000201:enzymology / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004492:Edetic Acid / Q000031:analogs & derivatives; D007502:Iron Chelating Agents; D009154:Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012318:RNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D007502:Iron Chelating Agents; D014157:Transcription Factors; C038200:methidiumpropyl-EDTA-iron(II); D004247:DNA; D004492:Edetic Acid; D012318:RNA Polymerase I