RRC ID 29810
Author Torrey TA, Kogoma T.
Title Genetic analysis of constitutive stable DNA replication in rnh mutants of Escherichia coli K12.
Journal Mol. Gen. Genet.
Abstract Escherichia coli rnh mutants deficient in ribonuclease H (RNase H) are capable of DNA replication in the absence of protein synthesis. This constitutive stable DNA replication (SDR) is dependent upon the recA+ gene product. The requirement of SDR for recA+ can be suppressed by rin mutations (for recA+-independent), or by lexA(Def) mutations which inactivate the LexA repressor. Thus, there are at least three genetically distinct types of SDR in rnh mutants: recA+-dependent SDR seen in rnh- rin+ lexA+ strains, recA+-independent in rnh- rin- lexA+, and recA+-independent in rnh- rin+ lexA(Def). The expression of SDR in rin- and lexA(Def) mutants demonstrated a requirement for RNA synthesis and for the absence of RNase H. The suppression of the recA+ requirement by rin mutations was shown to depend on some new function of the recF+ gene product. In contrast, the suppression by lexA-(Def) mutations was not dependent on recF+. The lexA3 mutation inhibited recA+-dependent SDR via reducing the amount of recA+ activity available, and was suppressed by the recAo254 mutation. The SDR in rnh- rin- cells was also inhibited by the lexA3 mutation, but the inhibition was not reversed by the recAo254 mutation, indicating a requirement for some other lexA+-regulated gene product in the recA+-independent SDR process. A model is presented for the regulation of the expression of these three types of SDR by the products of the lexA+, rin+ and recF+ genes.
Volume 208(3)
Pages 420-7
Published 1987-7
PMID 2823060
MeSH DNA Replication* Endoribonucleases / genetics* Escherichia coli / enzymology Escherichia coli / genetics* Escherichia coli / growth & development Genotype Kinetics Mutation* Ribonuclease H Species Specificity Temperature
Times Cited 18
Prokaryotes E. coli ME9244 ME9247 ME9248 ME9216 ME9210 ME9129 ME9234 ME9262 ME9251 ME9252 ME9254 ME9240 ME9241 ME9242 ME9243 ME9233 ME9221 ME9223 ME9267 ME9275 ME9265 ME9266