Base analog N6-hydroxylaminopurine mutagenesis in Escherichia coli: Genetic control and molecular specificity

Youri I. Pavlov, Valentin V. Suslov, Polina V. Shcherbakova, Thomas A. Kunkel, Akira Ono, Akira Matsuda, Roel M. Schaaper

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

We have studied the molecular specificity of the base analog N6-hydroxylaminopurine (HAP) in the E coli lacI gene, as well as the effects of mutations in DNA repair and replication genes on HAP mutagenesis. HAP induced base substitutions of the two transition types (A·T → G·C → and G·C → A·T) at equal frequency. This bi-directional transition specificity is consistent with in vitro primer extension experiments with the Klenow fragment of DNA polymerase I in which we observed that either dTTP or dCTP were incorporated opposite HAP in an oligonucleotide template. The spectrum of HAP-induced transitions was different from the spontaneous transitions in either a wild-type or a mismatch-repair-defective (mutL) strain. Mutations in genes controlling excision repair, exonucleolytic proofreading, mismatch correction, error-prone (SOS) repair and 8-oxo-guanine repair did not affect HAP-induced mutagenesis substantially. However, an extensive deletion of several genes in the uvrB-bio region conferred supersensitivity to the lethal and mutagenic effects of HAP, perhaps due to an effect on HAP metabolism. dnaE antimutator alleles reduced HAP-forward mutagenicity in allele-specific manner: dnaE911 reduced it several fold, while dnaE915 abolished it almost completely. The results obtained are consistent with the idea that HAP is mutagenic in E. coli via a pathway generating replication errors.

Original languageEnglish (US)
Pages (from-to)1-15
Number of pages15
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume357
Issue number1-2
DOIs
StatePublished - Oct 25 1996

Keywords

  • Antimutator DNA polymerase
  • Base analog N-hydroxylaminopurine
  • Escherichia coli
  • Mutagenic specificity
  • Δ(uvrB-bio) deletion

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis

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