title: Regulation of promoter-proximal transcription elongation: enhanced DNA scrunching drives λQ antiterminator-dependent escape from a σ70-dependent pause.
abstract: During initial transcription, RNA polymerase remains bound at the promoter and synthesizes RNA without movement along the DNA template, drawing downstream DNA into itself in a process called scrunching and thereby storing energy to sever the bonds that hold the enzyme at the promoter. We show that DNA scrunching also is the driving force behind the escape of RNA polymerase from a regulatory pause of the late gene operon of bacteriophage λ, and that this process is enhanced by the activity of the Q(λ) antiterminator. Furthermore, we show that failure of transcription complexes to escape the pause results in backtracking and arrest in a process analogous to abortive initiation. We identify a sequence element that modulates both abortive synthesis and the formation of arrested elongation complexes.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Strobel
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Roberts
mesh_terms: D004247:DNA / Q000737:chemistry*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005786:Gene Expression Regulation; D009154:Mutation; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D012808:Sigma Factor / Q000378:metabolism*; D061805:Transcription Elongation, Genetic; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: C066119:Q protein, Bacteriophage lambda; D012808:Sigma Factor; D014764:Viral Proteins; D004247:DNA; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases