Proofreading-defective DNA polymerase II increases adaptive mutation in Escherichia coli.
AUTOR(ES)
Foster, P L
RESUMO
The role of Escherichia coli DNA polymerase (Pol) II in producing or avoiding mutations was investigated by replacing the chromosomal Pol II gene (polB+) by a gene encoding an exonuclease-deficient mutant Pol II (polBex1). The polBex1 allele increased adaptive mutations on an episome in nondividing cells under lactose selection. The presence of a Pol III antimutator allele (dnaE915) reduced adaptive mutations in both polB+ cells and cells deleted for polB (polB delta 1) to below the wild-type level, suggesting that both Pol II and Pol III are synthesizing episomal DNA in nondividing cells but that in wild-type cells Pol III generates the adaptive mutations. The adaptive mutations were mainly -1 frame-shifts occurring in short homopolymeric runs and were similar in wild-type, polB delta 1, and polBex1 strains. Mutations produced by both Pol III and Pol II ex1 were corrected by the mutHLS mismatch repair system.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=41264Documentos Relacionados
- Involvement of Escherichia coli DNA polymerase II in response to oxidative damage and adaptive mutation.
- Transcriptional proofreading in Escherichia coli.
- Proofreading by the epsilon subunit of Escherichia coli DNA polymerase III increases the fidelity of calf thymus DNA polymerase alpha.
- A Mutant of Escherichia coli Defective in DNA Polymerase II Activity
- Error-Prone Polymerase, DNA Polymerase IV, Is Responsible for Transient Hypermutation during Adaptive Mutation in Escherichia coli
