Format

Send to

Choose Destination
Mol Cell Biol. 1989 Oct;9(10):4447-58.

Fidelity of DNA polymerase I and the DNA polymerase I-DNA primase complex from Saccharomyces cerevisiae.

Author information

1
Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.

Abstract

We have determined the fidelity of DNA synthesis by DNA polymerase I (yPol I) from Saccharomyces cerevisiae. To determine whether subunits other than the polymerase catalytic subunit influence fidelity, we measured the accuracy of yPol I purified by conventional procedures, which yields DNA polymerase with a partially proteolyzed catalytic subunit and no associated primase activity, and that of yPol I purified by immunoaffinity chromatography, which yields polymerase having a single high-molecular-weight species of the catalytic subunit, as well as three additional polypeptides and DNA primase activity. In assays that score polymerase errors within the lacZ alpha-complementation gene in M13mp2 DNA, yPol I and the yPol I-primase complex produced single-base substitutions, single-base frameshifts, and larger deletions. For specific errors and template positions, the two forms of polymerase exhibited differences in fidelity that could be as large as 10-fold. Nevertheless, results for the overall error frequency and the spectrum of errors suggest that the yPol I-DNA primase complex is not highly accurate and that, just as for the polymerase alone, its fidelity is not sufficient to account for a low spontaneous mutation rate in vivo. The specificity data also suggest models to explain -1 base frameshifts in nonrepeated sequences and certain complex deletions by a direct repeat mechanism involving aberrant loop-back synthesis.

PMID:
2555694
PMCID:
PMC362528
DOI:
10.1128/mcb.9.10.4447
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center