title: Association of RNA polymerase with transcribed regions in Escherichia coli.
abstract: We examine the association of the beta-, alpha-, and sigma(70)-subunits of Escherichia coli RNA polymerase (RNAP) and the NusA elongation factor with transcribed regions in vivo by using chromatin immunoprecipitation. RNAP preferentially associates with the promoter-proximal region of several operons, and this preference is particularly pronounced at the lexA-dinF promoter. When cells are grown in exponential phase, little or no sigma(70) is associated with RNAP during early elongation. However, during stationary phase, sigma(70) is retained in a fraction of elongating RNAP complexes throughout the melAB operon. In contrast, sigma(70) is not observed in elongating RNAP complexes at the lacZYA operon during stationary phase. At both operons, NusA associates with RNAP during early elongation, and this association is greatly reduced during stationary phase. These observations suggest that in vivo association of sigma(70) and NusA with elongating RNAP is regulated by growth conditions.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Wade
authors.forename: Kevin
authors.initials: K
authors.lastname: Struhl
mesh_terms: D047369:Chromatin Immunoprecipitation; D004247:DNA / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D009876:Operon / Q000235:genetics; D010445:Peptide Elongation Factors / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012808:Sigma Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D035602:Transcriptional Elongation Factors
chemical_list: D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; D012808:Sigma Factor; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C068727:nusA protein, E coli; D004247:DNA; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases