title: Modulation of DNA repair by mutations flanking the DNA channel through RNA polymerase.
abstract: The RuvABC and RecBCD proteins promote rescue of stalled or broken DNA replication forks in Escherichia coli. Strains lacking these proteins cope poorly with DNA damage and have problems with chromosome segregation and cell division. We show how these difficulties are overcome to varying degrees by a sub-class of RNA polymerase mutations selected for their stringent phenotype. Thirty-five mutations were sequenced. All but one change single amino acids in RpoB or RpoC that lie on or near the path taken by DNA through the enzyme, indicating they may affect the stability of transcription complexes. Four mutant enzymes are shown to form unstable open complexes at the lambdacro promoter. At least one may also release stalled complexes or limit their formation, as it reduces the need for reactivation of transcription by GreA or GreB, and for transcription-coupled DNA repair of UV damage by Mfd. The results shed light on the interplay between DNA replication and transcription and suggest ways in which conflicts between these two vital cellular processes are avoided or resolved.
authors.affiliation: Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Brigitte W
authors.initials: BW
authors.lastname: Trautinger
authors.forename: Robert G
authors.initials: RG
authors.lastname: Lloyd
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004351:Drug Resistance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D029968:Escherichia coli Proteins; D008858:Microscopy, Phase-Contrast; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D011487:Protein Conformation; D012293:Rifampin / Q000494:pharmacology; D013379:Substrate Specificity; D013824:Thermus / Q000201:enzymology; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; C079667:GreB protein, E coli; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C075886:GREA protein, Rickettsia prowazekii; D004247:DNA; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D012293:Rifampin