Two modes of excision repair in toluene-treated Escherichia coli

R Sharon, C Miller, R Ben-Ishai
1975 Journal of Bacteriology  
In toluene-treated Escherichia coli incision breaks accumulate during postirradiation incubation in the presence of adenosine 5'-triphosphate (ATP). It is shown that incised deoxyribonucleic acid (DNA) is converted to high-molecularweight DNA during reincubation in the presence of the four deoxyribonucleoside triphosphates (dNTP's) and nicotinamide adenine dinucleotide (NAD). This restitution process is ATP independent and N-ethylmaleimide insensitive and takes place only in pQlA+ strains. It
more » ... pQlA+ strains. It is defective in strains carrying a mutation in the 5' -_ 3' exonucleolytic activity associated with DNA polymerase I. Repair of accumulated incision breaks differs from repair in which all the steps of the excision repair process occur simultaneously or in rapid succession. The latter is observed if toluene-treated E. coli are incubated immediately after irradiation in the presence of the four dNTP's, NAD, and ATP. It is shown that under these conditions dimer excision occurs to a larger extent than during repair of accumulated incision breaks and that, except in strains defective in polynucleotide ligase, incision breaks do not accumulate. This consecutive mode of repair is detectable in polA+ strains and at low doses also in polA mutants.
doi:10.1128/jb.123.3.1107-1114.1975 fatcat:vngi2ugmpzfelgpn4hj2yb3mlu