title: The cell surface protein Ag43 facilitates phage infection of Escherichia coli in the presence of bile salts and carbohydrates.
abstract: It was found that infection of Escherichia coli by bacteriophage lambda is inhibited in the presence of certain bile salts and carbohydrates when cells are in the "OFF" state for production of the phase-variable cell surface protein antigen 43 (Ag43). The inhibition of phage growth was found to be due to a significant impairment in the process of phage adsorption. Expression of the gene encoding Ag43 (agn43) from a plasmid or inactivation of the oxyR gene (encoding an activator of genes important for defence against oxidative stress) suppressed this inhibition. A mutation, rpoA341, in the gene encoding the alpha subunit of RNA polymerase also facilitated phage adsorption in the presence of bile salts and carbohydrates. The rpoA341 mutation promoted efficient production of Ag43 in a genetic background that would otherwise be in the "OFF" phase for expression of the agn43 gene. Analysis of a reporter gene fusion demonstrated that the promoter for the agn43 gene was more active in the rpoA341 mutant than in the otherwise isogenic rpoA(+) strain. The combined inhibitory action of bile salts and carbohydrates on phage adsorption and the abolition of this inhibition by production of Ag43 was not restricted to lambda, as a similar phenomenon was observed for the coliphages P1 and T4.
authors: Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland.
authors: Magdalena
authors: M
authors: Gabig
authors: Anna
authors: A
authors: Herman-Antosiewicz
authors: Marta
authors: M
authors: Kwiatkowska
authors: Marcin
authors: M
authors: Los
authors: Mark S
authors: MS
authors: Thomas
authors: Grzegorz
authors: G
authors: Wegrzyn
mesh_terms: D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; D000327:Adsorption / Q000187:drug effects; D000940:Antigenic Variation; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010582:Bacteriophage lambda / Q000187:drug effects* / Q000502:physiology*; D001647:Bile Acids and Salts / Q000494:pharmacology*; D002241:Carbohydrates / Q000494:pharmacology*; D002413:Cations, Divalent / Q000378:metabolism; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism* / Q000821:virology*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007785:Lactose / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects
chemical_list: D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001647:Bile Acids and Salts; D002241:Carbohydrates; D002413:Cations, Divalent; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C118376:antigen 43, E coli; C499299:oxyR protein, E coli; D006861:Hydrogen Peroxide; D012321:DNA-Directed RNA Polymerases; C113275:RNA polymerase alpha subunit; D007785:Lactose