Mutagenic bypass of 8-oxo-7,8-dihydroguanine (8-hydroxyguanine) by DNA polymerase κ in human cells.
The formation of 8-oxo-7,8-dihydroguanine (G(O), 8-hydroxyguanine) in DNA and in the nucleotide pool results in G:C→T:A and A:T→C:G substitution mutations, respectively, since G(O) can pair with both C and A. In this study, the role of DNA polymerase κ in the mutagenicity of G(O) was investigated, using a supF shuttle plasmid propagated in human U2OS cells. This translesion synthesis DNA polymerase was knocked down by siRNA, and plasmid DNAs containing G(O):C and G(O):A pairs were transfected into the knock-down cells. The supF plasmid DNAs replicated in the cells were then introduced into Escherichia coli. Mutation analyses indicated that the knock-down of DNA polymerase κ by siRNA decreased the frequency of G:C→T:A mutation caused by G(O):C, although no effects of the DNA polymerase κ reduction were observed for the A:T→C:G substitution induced by G(O):A. These results suggested that DNA polymerase κ is involved in the mutagenic bypass of G(O) in living human cells, when the damaged base is generated by direct DNA oxidation.
Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan. hirokam@ehime-u.ac.jp
Hiroyuki
H
Kamiya
Masahiro
M
Kurokawa
D020029:Base Pairing; D045744:Cell Line, Tumor; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D009154:Mutation; D019384:Nucleic Acid Synthesis Inhibitors; D010957:Plasmids / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D000099270:Y-Family DNA Polymerases
D004247:DNA; D004259:DNA-Directed DNA Polymerase; D006147:Guanine; D019384:Nucleic Acid Synthesis Inhibitors; D034741:RNA, Small Interfering; C024829:8-hydroxyguanine; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases