Division of Labor at the Eukaryotic Replication Fork

• Published in: Molecular cell Vol. 30; no. 2; pp. 137 - 144
• Main Authors: Nick McElhinny, Stephanie A., Gordenin, Dmitry A., Stith, Carrie M., Burgers, Peter M.J., Kunkel, Thomas A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 25.04.2008
• Subjects: Alleles; CELLCYCLE; DNA; DNA Mismatch Repair; DNA Mutational Analysis; DNA Polymerase II - genetics; DNA Polymerase II - metabolism; DNA Polymerase III; DNA Replication; Genes, Reporter; Models, Biological; Mutation; MutS Homolog 2 Protein - genetics; MutS Homolog 2 Protein - metabolism; Replication Origin; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; CELLCYCLE; DNA
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2008.02.022

DNA polymerase δ (Pol δ) and DNA polymerase ɛ (Pol ɛ) are both required for efficient replication of the nuclear genome, yet the division of labor between these enzymes has remained unclear for many years. Here we investigate the contribution of Pol δ to replication of the leading and lagging strand templates in Saccharomyces cerevisiae using a mutant Pol δ allele (pol3-L612M) whose error rate is higher for one mismatch (e.g., T•dGTP) than for its complement (A•dCTP). We find that strand-specific mutation rates strongly depend on the orientation of a reporter gene relative to an adjacent replication origin, in a manner implying that >90% of Pol δ replication is performed using the lagging strand template. When combined with recent evidence implicating Pol ɛ in leading strand replication, these data support a model of the replication fork wherein the leading and lagging strand templates are primarily copied by Pol ɛ and Pol δ, respectively.