This Article Full Text Full Text (PDF) Other Versions of this Article: JB.00476-07v1 189/13/4688    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Maul, R. W. Articles by Sutton, M. D. Search for Related Content PubMed PubMed Citation Articles by Maul, R. W. Articles by Sutton, M. D.

Role of Escherichia coli DNA Polymerase I in Conferring Viability upon the dnaN159 Mutant Strain

Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 3435 Main Street, 140 Farber Hall, Buffalo, New York 14214

Received 29 March 2007/ Accepted 13 April 2007

The Escherichia coli dnaN159 allele encodes a mutant form of the ß-sliding clamp (ß159) 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 ß clamp stimulates the processivity of Pol I in vitro and that ß159 is impaired for this activity. The reduced ability of ß159 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 ß 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 polA strain.

Published ahead of print on 20 April 2007.