We have previously shown that some Escherichia coli (derivatives of strain HS432 (polA1, polB100, polC1026) can replicate DNA at a restrictive temperature in the presence of a polCts mutation and that such revertants contain apparent DNA polymerase I activity. We demonstrate here that this strain of E. coli becomes temperature-resistant upon the introduction of a normal gene for DNA polymerase I or suppression of the polA1 nonsense mutation. Such temperature-resistant phenocopies become temperature-sensitive upon introduction of a temperature-sensitive DNA polymerase I gene. Our results confirm that DNA replication is DNA polymerase I-dependent in the temperature resistant revertants, indicating that an alternative pathway of replication exists in E. coli. HS432 contains a transducible locus (which we term pcbA) that can support an alternate pathway in other E. coli strains, so the effect of suppression of polCts is a general one.
|Original language||English (US)|
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Issue number||11 II|
|State||Published - Dec 1 1981|
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