Incorporation of 8-hydroxyguanosine (8-oxo-7,8-dihydroguanosine) 5'-triphosphate by bacterial and human RNA polymerases.
Oxidized RNA precursors formed in the nucleotide pool may be incorporated into RNA. In this study, the incorporation of 8-hydroxyguanosine 5'-triphosphate (8-OH-GTP; 8-oxo-7,8-dihydroguanosine 5'-triphosphate) into RNA by Escherichia coli RNA polymerase was examined in vitro, using a primer RNA and a template DNA with defined sequences. 8-OH-GTP was incorporated opposite C and A in the template DNA. Surprisingly, 8-OH-GTP was quite efficiently incorporated by the bacterial RNA polymerase, in contrast to the incorporation of the 2'-deoxyribo counterpart by DNA polymerases, as indicated by the kinetic parameters. The primer was further extended by the addition of a ribonucleotide complementary to the nucleobase adjacent to C or A (the nucleobase opposite which 8-OH-GTP was inserted). Thus, the incorporation of 8-OH-GTP did not completely inhibit further RNA chain elongation. 8-OH-GTP was also incorporated opposite C and A by human RNA polymerase II. These results suggest that 8-OH-GTP in the nucleotide pool can cause the formation of oxidized RNA and disturb the transmittance of genetic information.
Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan. hirokam@pharm.hokudai.ac.jp
Hiroyuki
H
Kamiya
Akihiro
A
Suzuki
Yuki
Y
Yamaguchi
Hiroshi
H
Handa
Hideyoshi
H
Harashima
D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003848:Deoxyguanine Nucleotides / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D012329:RNA, Bacterial / Q000187:drug effects / Q000378:metabolism; D012265:Ribonucleotides / Q000494:pharmacology
D003848:Deoxyguanine Nucleotides; D012329:RNA, Bacterial; D012265:Ribonucleotides; C078206:8-oxodeoxyguanosine triphosphate; D012321:DNA-Directed RNA Polymerases