title: Mutational specificity and genetic control of replicative bypass of an abasic site in yeast.
abstract: Abasic (AP) sites represent one of the most frequently formed lesions in DNA, and they present a strong block to continued synthesis by the replicative DNA polymerases (Pols). Here we determine the mutational specificity and the genetic control of translesion synthesis (TLS) opposite an AP site in yeast by using a double-stranded plasmid system that we have devised in which bidirectional replication proceeds from a replication origin. We find that the rate, the genetic control, and the types and frequencies of nucleotides inserted opposite the AP site are very similar for both the leading and the lagging DNA strands, and that an A is predominantly inserted opposite the AP site, whereas C insertion by Rev1 constitutes a much less frequent event. In striking contrast, in studies that have been reported previously for AP bypass with gapped-duplex and single-stranded plasmids, it has been shown that a C is the predominant nucleotide inserted opposite the AP site. We discuss the implications of our observations for the mechanisms of TLS on the leading versus the lagging DNA strand and suggest that lesion bypass during replication involves the coordination of activities of the replicative Pol with that of the lesion-bypass Pol.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1061, USA.
authors.forename: Vincent
authors.initials: V
authors.lastname: Pagès
authors.forename: Robert E
authors.initials: RE
authors.lastname: Johnson
authors.forename: Louise
authors.initials: L
authors.lastname: Prakash
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
mesh_terms: D000227:Adenine Nucleotides / Q000235:genetics; D003597:Cytosine Nucleotides / Q000235:genetics; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D004789:Enzyme Activation / Q000235:genetics; D016368:Frameshift Mutation; D016254:Mutagenesis, Insertional; D009713:Nucleotidyltransferases / Q000235:genetics; D010957:Plasmids; D018741:Replication Origin / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D000099270:Y-Family DNA Polymerases
chemical_list: D000227:Adenine Nucleotides; D003597:Cytosine Nucleotides; D004271:DNA, Fungal; D004259:DNA-Directed DNA Polymerase; D009713:Nucleotidyltransferases; D029701:Saccharomyces cerevisiae Proteins; C425929:DNA polymerase zeta; C100951:REV1 protein, S cerevisiae; D000099270:Y-Family DNA Polymerases; C112338:Rad30 protein