title: Effects of the C4'-oxidized abasic site on replication in Escherichia coli. An unusually large deletion is induced by a small lesion.
abstract: The C4'-oxidized abasic site (C4-AP) is produced in DNA as a result of oxidative stress by a variety of agents. For instance, the lesion accounts for approximately 40% of the DNA damage produced by the antitumor antibiotic bleomycin. The effect of C4-AP on DNA replication in Escherichia coli was determined using the restriction endonuclease and postlabeling (REAP) method. Three-nucleotide deletion products are the sole products observed following replication of plasmids containing C4-AP under SOS conditions in wild-type cells. Full-length products are formed in varying amounts depending upon the local sequence in wild-type cells under non-SOS-induced conditions. The "A-rule" is followed for the formation of substitution products. C4-AP is the first example of a DNA lesion that produces significant levels of three-nucleotide deletions in a variety of sequence contexts. Experiments carried out in cells lacking specific polymerases reveal that formation of three-nucleotide deletion products results from a coordinated effort involving pol II and pol IV. This is the first example in which these SOS inducible polymerases are shown to work in concert during lesion bypass. Three-nucleotide deletions are not observed during the replication of other abasic lesions, and are rarely produced by bulky adducts. The effect of C4-AP on DNA replication suggests a significant role for this lesion in the cytotoxicity of bleomycin. Formation of the C4-AP lesion may also be responsible for the formation of mutant proteins containing single-amino acid deletions that exhibit altered phenotypes.
authors.affiliation: Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Kroeger
authors.forename: Jaeseung
authors.initials: J
authors.lastname: Kim
authors.forename: Myron F
authors.initials: MF
authors.lastname: Goodman
authors.forename: Marc M
authors.initials: MM
authors.lastname: Greenberg
mesh_terms: D001080:Apurinic Acid / Q000737:chemistry*; D001483:Base Sequence; D004249:DNA Damage; D004261:DNA Replication / Q000528:radiation effects; D004269:DNA, Bacterial / Q000737:chemistry* / Q000528:radiation effects; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics* / Q000528:radiation effects; D006358:Hot Temperature; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry / Q000528:radiation effects; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000235:genetics / Q000528:radiation effects; D010957:Plasmids; D017384:Sequence Deletion; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D009692:Nucleic Acid Heteroduplexes; D009841:Oligonucleotides; D001080:Apurinic Acid