Involvement of Escherichia coli exonuclease III and endonuclease IV in the repair of singlet oxygen-induced DNA damage
Open Access
- 1 January 1996
- journal article
- Published by Oxford University Press (OUP) in Carcinogenesis: Integrative Cancer Research
- Vol. 17 (5) , 1183-1185
- https://doi.org/10.1093/carcin/17.5.1183
Abstract
Singlet molecular oxygen (1O2 has been implicated in several biological processes that may lead to genetic damage. The relevance of various repair pathways in plasmid inactivation mediated by 1O2 was investigated. Plasmid treated with 1O2, chemically generated, was transfected into Escherichia coli strains deficient in genes implicated in the DNA repair of oxidative damage. The ability to transform bacteria is significantly reduced in the double mutant xth,nfo, deficient in both exonuclease HI and endo-nuclease IV, although it was similar to wild-type cells in single mutants. The products of these two genes are able to cleave DNA damaged by 1O2 and to remove DNA polymerization blocks from 3′-termini enerated either directly by 1O2 treatment or after the action of the formami-dopyrimidine-DNA-N-glycosylase (Fpg protein). The results indicate that the exonuclease III and endonuclease IV participate in the excision of lethal lesions induced in DNA by 1O2Keywords
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