title: Photo-cross-linking of a purified preinitiation complex reveals central roles for the RNA polymerase II mobile clamp and TFIIE in initiation mechanisms.
abstract: The topological organization of a TATA binding protein-TFIIB-TFIIF-RNA polymerase II (RNAP II)-TFIIE-promoter complex was analyzed using site-specific protein-DNA photo-cross-linking of gel-purified complexes. The cross-linking results for the subunits of RNAP II were used to determine the path of promoter DNA against the structure of the enzyme. The results indicate that promoter DNA wraps around the mobile clamp of RNAP II. Cross-linking of TFIIF and TFIIE both upstream of the TATA element and downstream of the transcription start site suggests that both factors associate with the RNAP II mobile clamp. TFIIE alpha closely approaches promoter DNA at nucleotide -10, a position immediately upstream of the transcription bubble in the open complex. Increased stimulation of transcription initiation by TFIIE alpha is obtained when the DNA template is artificially premelted in the -11/-1 region, suggesting that TFIIE alpha facilitates open complex formation, possibly through its interaction with the upstream end of the partially opened transcription bubble. These results support the central roles of the mobile clamp of RNAP II and TFIIE in transcription initiation.
authors.affiliation: Laboratory of Gene Transcription, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada H2W 1R7.
authors.forename: Diane
authors.initials: D
authors.lastname: Forget
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Langelier
authors.forename: Cynthia
authors.initials: C
authors.lastname: Thérien
authors.forename: Vincent
authors.initials: V
authors.lastname: Trinh
authors.forename: Benoit
authors.initials: B
authors.lastname: Coulombe
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*; D015003:Yeasts / Q000235:genetics / Q000502:physiology
chemical_list: D019473:Transcription Factors, TFII; C066644:transcription factor TFIIE; D012319:RNA Polymerase II