Correlation of activity with phenotypes of Escherichia coli partial function mutants of rnh, the gene encoding RNase H

Mitsuhiro Itaya, Robert J. Crouch

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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)].

Original languageEnglish
Pages (from-to)433-437
Number of pages5
JournalMGG Molecular & General Genetics
Issue number3
Publication statusPublished - 1991 Jul 1



  • RNase H
  • dnaA
  • recBCD

ASJC Scopus subject areas

  • Genetics

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