Open AccessRetention of replication fidelity by a DNA polymerase functioning in a distantly related environment
Author(s) -
Holly K. Dressman,
Chien Chia Wang,
J.D. Karam,
John W. Drake
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.15.8042
Subject(s) - biology , proofreading , dna replication , dna polymerase , genetics , polymerase , genome , dna , gene
The primary structures of the replicative DNA polymerases (gp43s) of bacteriophage T4 and its distant phylogenetic relative RB69 are diverged, retaining only 61% identity and 74% similarity. Nevertheless, RB69 gp43 substitutes effectively for T4 gp43 in T4 DNA replicationin vivo . We show here that RB69 gp43 replicates T4 genomesin vivo with a fidelity similar to that achieved by T4 gp43. Furthermore, replication by RB69 gp43 in the distantly related environment does not enhance the mutator activities of mutations in T4 genes that encode other components of the multienzyme DNA replicase. We also show that the fidelities of RB69 gp43 and T4 gp43 are both highin vitro and that they are similarly and sharply reducedin vivo by mutations that eliminate the 3′-exonucleolytic proofreading function. We conclude that gp43 interactions with the other replication proteins are probably nonessential for polymerase fidelity.