Characterization of the repeat-tract instability and mutator phenotypes conferred by a Tn3 insertion in RFC1, the large subunit of the yeast clamp loader.

Journal Article (Journal Article)

The RFC1 gene encodes the large subunit of the yeast clamp loader (RFC) that is a component of eukaryotic DNA polymerase holoenzymes. We identified a mutant allele of RFC1 (rfc1::Tn3) from a large collection of Saccharomyces cerevisiae mutants that were inviable when present in a rad52 null mutation background. Analysis of rfc1::Tn3 strains indicated that they displayed both a mutator and repeat-tract instability phenotype. Strains bearing this allele were characterized in combination with mismatch repair (msh2Delta, pms1Delta), double-strand break repair (rad52), and DNA replication (pol3-01, pol30-52, rth1Delta/rad27Delta) mutations in both forward mutation and repeat-tract instability assays. This analysis indicated that the rfc1::Tn3 allele displays synthetic lethality with pol30, pol3, and rad27 mutations. Measurement of forward mutation frequencies in msh2Delta rfc1:Tn3 and pms1Delta rfc1:Tn3 strains indicated that the rfc1::Tn3 mutant displayed a mutation frequency that appeared nearly multiplicative with the mutation frequency exhibited by mismatch-repair mutants. In repeat-tract instability assays, however, the rfc1::Tn3 mutant displayed a tract instability phenotype that appeared epistatic to the phenotype displayed by mismatch-repair mutants. From these data we propose that defects in clamp loader function result in DNA replication errors, a subset of which are acted upon by the mismatch-repair system.

Full Text

Duke Authors

Cited Authors

  • Xie, Y; Counter, C; Alani, E

Published Date

  • February 1999

Published In

Volume / Issue

  • 151 / 2

Start / End Page

  • 499 - 509

PubMed ID

  • 9927446

Pubmed Central ID

  • PMC1460510

International Standard Serial Number (ISSN)

  • 0016-6731

Digital Object Identifier (DOI)

  • 10.1093/genetics/151.2.499


  • eng

Conference Location

  • United States