Role of Escherichia coli DNA polymerase I in conferring viability upon the dnaN159 mutant strain.


Journal Article

The Escherichia coli dnaN159 allele encodes a mutant form of the beta-sliding clamp (beta159) that is impaired for interaction with the replicative DNA polymerase (Pol), Pol III. In addition, strains bearing the dnaN159 allele require functional Pol I for viability. We have utilized a combination of genetic and biochemical approaches to characterize the role(s) played by Pol I in the dnaN159 strain. Our findings indicate that elevated levels of Pol I partially suppress the temperature-sensitive growth phenotype of the dnaN159 strain. In addition, we demonstrate that the beta clamp stimulates the processivity of Pol I in vitro and that beta159 is impaired for this activity. The reduced ability of beta159 to stimulate Pol I in vitro correlates with our finding that single-stranded DNA (ssDNA) gap repair is impaired in the dnaN159 strain. Taken together, these results suggest that (i) the beta clamp-Pol I interaction may be important for proper Pol I function in vivo and (ii) in the absence of Pol I, ssDNA gaps may persist in the dnaN159 strain, leading to lethality of the dnaN159 DeltapolA strain.

Full Text

Duke Authors

Cited Authors

  • Maul, RW; Sanders, LH; Lim, JB; Benitez, R; Sutton, MD

Published Date

  • July 2007

Published In

Volume / Issue

  • 189 / 13

Start / End Page

  • 4688 - 4695

PubMed ID

  • 17449610

Pubmed Central ID

  • 17449610

International Standard Serial Number (ISSN)

  • 0021-9193

Digital Object Identifier (DOI)

  • 10.1128/JB.00476-07


  • eng

Conference Location

  • United States