title: Correlation of activity with phenotypes of Escherichia coli partial function mutants of rnh, the gene encoding RNase H.
abstract: The rnh gene of Escherichia coli encodes RNase H. rnh mutants display at least two phenotypes: (1) they require functional RecBCD enzyme for growth; thus rnh-339::cat recB270 (Ts) and rnh-339::cat recC271 (Ts) strains are temperature sensitive for growth; (2) rnh mutants permit replication that is independent of the chromosomal origin, presumably by failing to remove RNA-DNA hybrids from which extra-original replication can be primed. We report here that manifestation of these two phenotypes occurs at different levels of RNase H function; we have examined partially functional rnh mutants for their in vitro RNase H activity, their ability to rescue viability in recB or recC cells and their ability to permit growth of mutants incapable of using oriC [dnaA (Ts)].
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: M
authors.initials: M
authors.lastname: Itaya
authors.forename: R J
authors.initials: RJ
authors.lastname: Crouch
mesh_terms: D000483:Alleles; D004722:Endoribonucleases / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D005798:Genes, Bacterial; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D010957:Plasmids; D016914:Ribonuclease H; D013696:Temperature
chemical_list: D004722:Endoribonucleases; D016914:Ribonuclease H