title: Initial transcribed region sequences influence the composition and functional properties of the bacterial elongation complex.
abstract: The bacterial RNA polymerase (RNAP) holoenzyme consists of a catalytic core enzyme (α(2)ββ'ω) in complex with a σ factor that is essential for promoter recognition and transcription initiation. During early elongation, the stability of interactions between σ and the remainder of the transcription complex decreases. Nevertheless, there is no mechanistic requirement for release of σ upon the transition to elongation. Furthermore, σ can remain associated with RNAP during transcription elongation and influence regulatory events that occur during transcription elongation. Here we demonstrate that promoter-like DNA sequence elements within the initial transcribed region that are known to induce early elongation pausing through sequence-specific interactions with σ also function to increase the σ content of downstream elongation complexes. Our findings establish σ-dependent pausing as a mechanism by which initial transcribed region sequences can influence the composition and functional properties of the transcription elongation complex over distances of at least 700 base pairs.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Padraig
authors.initials: P
authors.lastname: Deighan
authors.forename: Chirangini
authors.initials: C
authors.lastname: Pukhrambam
authors.forename: Bryce E
authors.initials: BE
authors.lastname: Nickels
authors.forename: Ann
authors.initials: A
authors.lastname: Hochschild
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D012808:Sigma Factor / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases