In search of a mutational hotspot.
In vitro selection was used to define sequence contexts that significantly enhanced the mutagenic potential of 7, 8-dihydro-8-oxoguanine (8-oxoG). Contexts that simultaneously reduced the efficiency of 8-oxoG cleavage by formamidopyrimidine DNA N-glycosylase and increased the efficiency of misincorporating A opposite the lesion by DNA polymerase were isolated from a pool of 4(8) random octanucleotide sequences. Kinetic analysis showed that the combined effects of poor repair and high miscoding resulted in 10(2)- to 10(3)-fold increase in the mutagenic potential of 8-oxoG. Furthermore, the isolated sequence contexts correlated strongly with G --> T transversion hotspots in spontaneous mutational spectra reported for the Escherichia coli lacI and human p53 and factor IX genes. We present an example directly linking the interplay between DNA repair and replication to a "high risk sequence" for base substitution.
Department of Microbiology and Molecular Genetics and the Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405, USA.
Z
Z
Hatahet
M
M
Zhou
L J
LJ
Reha-Krantz
S W
SW
Morrical
S S
SS
Wallace
D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D016384:Consensus Sequence; D004247:DNA; D004249:DNA Damage; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005164:Factor IX / Q000235:genetics; D016158:Genes, p53; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D056968:Lac Repressors; D008969:Molecular Sequence Data; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics; D014764:Viral Proteins / Q000378:metabolism
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D056968:Lac Repressors; C539064:LacI protein, E coli; D012097:Repressor Proteins; D014764:Viral Proteins; C069983:gene 43 protein, Enterobacteria phage T4; C024829:8-hydroxyguanine; D006147:Guanine; D005164:Factor IX; D004247:DNA; D004259:DNA-Directed DNA Polymerase