Position of the general transcription factor TFIIF within the RNA polymerase II transcription preinitiation complex.
The RNA polymerase (pol) II general transcription factor TFIIF functions at several steps in transcription initiation including preinitiation complex (PIC) formation and start site selection. We find that two structured TFIIF domains bind Pol II at separate locations far from the active site with the TFIIF dimerization domain on the Pol II lobe and the winged helix domain of the TFIIF small subunit Tfg2 above the Pol II protrusion where it may interact with upstream promoter DNA. Binding of the winged helix to the protrusion is PIC specific. Anchoring of these two structured TFIIF domains at separate sites locates an essential and unstructured region of Tfg2 near the Pol II active site cleft where it may interact with flexible regions of Pol II and the general factor TFIIB to promote initiation and start site selection. Consistent with this mechanism, mutations far from the enzyme active site, which alter the binding of either structured TFIIF domains to Pol II, have similar defects in transcription start site usage.
Eichner
Jesse
J
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Chen
Hung-Ta
HT
Warfield
Linda
L
Hahn
Steven
S
D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers / Q000235:genetics; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D009154:Mutation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019473:Transcription Factors, TFII / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
D017931:DNA Primers; D046912:Multiprotein Complexes; D021122:Protein Subunits; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D019473:Transcription Factors, TFII; D012319:RNA Polymerase II; C056604:transcription factor TFIIF