title: Excision repair of thymine glycols, urea residues, and apurinic sites in Escherichia coli.
abstract: The genetic requirements for the excision repair of thymine glycols, urea residues, and apurinic (AP) sites were examined by measuring the survival in Escherichia coli mutants of phi X174 replicative form (RF) I transfecting DNA containing selectively introduced lesions. phi X RF I DNA containing thymine glycols was inactivated at a greater rate in mutants deficient in endonuclease III (nth) than in wild-type hosts, suggesting that endonuclease III is involved in the repair of thymine glycols in vivo. phi X RF I DNA containing thymine glycols was also inactivated at a greater rate in mutants that were deficient in both exonuclease III and endonuclease IV (xth nfo) than in wild-type hosts, suggesting that a class II AP endonuclease is required for the in vivo processing of thymine glycols. phi X duplex-transfecting DNA containing urea residues or AP sites was inactivated at a greater rate in xth nfo double mutants than in wild-type, but not single-mutant, hosts, suggesting that exonuclease III or endonuclease IV is required for the repair of these damages and that either activity can substitute for the other. These data are in agreement with the known in vitro substrate specificities of endonuclease III, exonuclease III, and endonuclease IV.
authors: Department of Microbiology, New York Medical College, Valhalla 10595.
authors: M F
authors: MF
authors: Laspia
authors: S S
authors: SS
authors: Wallace
mesh_terms: D003090:Coliphages / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair; D004269:DNA, Bacterial / Q000032:analysis / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043224:Deoxyribonuclease (Pyrimidine Dimer); D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D013014:SOS Response, Genetics; D013379:Substrate Specificity; D013941:Thymine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism; D014162:Transfection; D014466:Ultraviolet Rays; D014508:Urea / Q000032:analysis / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C029389:thymine glycol; D014508:Urea; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D013941:Thymine