title: A three-step pathway of transcription initiation leading to promoter clearance at an activation RNA polymerase II promoter.
abstract: The progress of transcription bubbles during inhibition in vitro was followed in order to learn how RNA polymerase II begins transcription at the activated adenovirus E4 promoter. The issues addressed include the multiple roles of ATP, the potential effect of polymerase C-terminal domain phosphorylation, and the ability of polymerase to clear the promoter for reinitiation. The results lead to a three-step model for the transition from closed complex to elongation complex, two steps of which use ATP independently. In the first step, studied previously, ATP is hydrolyzed to open the DNA strands over the start site. In a second step, apparently independent of ATP, transcription bubbles move into the initial transcribed region where RNA synthesis can stall. In the third step, transcripts can be made as polymerase is released from these stalled positions with the assistance of an ATP-dependent process, likely phosphorylation of the polymerase C-terminal domain. After this third step, the promoter becomes cleared, allowing for the reinitiation of transcription.
authors.affiliation: Department of Chemistry and Biochemistry, University of California at Los Angeles, 90095-1569, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.forename: M
authors.initials: M
authors.lastname: Yan
authors.forename: J D
authors.initials: JD
authors.lastname: Gralla
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017504:Adenovirus E4 Proteins / Q000235:genetics; D001483:Base Sequence; D018387:Codon, Initiator; D004789:Enzyme Activation; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D017504:Adenovirus E4 Proteins; D018387:Codon, Initiator; D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D011494:Protein Kinases; C060137:carboxy-terminal domain kinase; D012319:RNA Polymerase II