title: Levels of epsilon, an essential replication subunit of Escherichia coli DNA polymerase III, are controlled by heat shock proteins.
abstract: In Escherichia coli, epsilon, the proofreading subunit of DNA polymerase III, is encoded by dnaQ. A random search for mutants that affect the expression of dnaQ revealed that mutations in the genes encoding the heat shock proteins (HSPs) DnaK, DnaJ, and GrpE result in dramatic decreases in the cellular levels of epsilon. dnaQ is arranged in an overlapping divergent transcriptional unit with rnhA, which encodes RNase H1, and mutations in the same HSPs also reduced the apparent levels of RNase H1. The HSPs had only small effects on transcriptional fusions to these genes; thus, it is likely that they operate primarily at the protein level. Since survival and mutagenesis after DNA damage are affected by epsilon and RNase H1, HSPs may have a broad influence on various aspects of DNA replication and repair.
authors.affiliation: Department of Environmental Health, Boston University School of Public Health, Massachusetts 02118.
authors.forename: P L
authors.initials: PL
authors.lastname: Foster
authors.forename: M G
authors.initials: MG
authors.lastname: Marinus
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D004258:DNA Polymerase III / Q000378:metabolism*; D004261:DNA Replication / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D007763:Lac Operon; D046911:Macromolecular Substances; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000096:biosynthesis; D016914:Ribonuclease H / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D011994:Recombinant Proteins; D004258:DNA Polymerase III; D016914:Ribonuclease H; D001616:beta-Galactosidase