title: Structural visualization of key steps in human transcription initiation.
abstract: Eukaryotic transcription initiation requires the assembly of general transcription factors into a pre-initiation complex that ensures the accurate loading of RNA polymerase II (Pol II) at the transcription start site. The molecular mechanism and function of this assembly have remained elusive due to lack of structural information. Here we have used an in vitro reconstituted system to study the stepwise assembly of human TBP, TFIIA, TFIIB, Pol II, TFIIF, TFIIE and TFIIH onto promoter DNA using cryo-electron microscopy. Our structural analyses provide pseudo-atomic models at various stages of transcription initiation that illuminate critical molecular interactions, including how TFIIF engages Pol II and promoter DNA to stabilize both the closed pre-initiation complex and the open-promoter complex, and to regulate start--initiation complexes, combined with the localization of the TFIIH helicases XPD and XPB, support a DNA translocation model of XPB and explain its essential role in promoter opening.
authors: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors: Yuan
authors: Y
authors: He
authors: Jie
authors: J
authors: Fang
authors: Dylan J
authors: DJ
authors: Taatjes
authors: Eva
authors: E
authors: Nogales
mesh_terms: D001483:Base Sequence; D020285:Cryoelectron Microscopy; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D035181:TATA-Box Binding Protein / Q000737:chemistry / Q000378:metabolism; D051758:Transcription Factor TFIIH / Q000737:chemistry / Q000378:metabolism; D019473:Transcription Factors, TFII / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D024363:Transcription Initiation Site; D061785:Transcription Initiation, Genetic / Q000502:physiology*
chemical_list: D035181:TATA-Box Binding Protein; D019473:Transcription Factors, TFII; C066644:transcription factor TFIIE; D051758:Transcription Factor TFIIH; D004247:DNA; D012319:RNA Polymerase II; D004265:DNA Helicases; C056604:transcription factor TFIIF