Effects of overexpression and antisense RNA expression of Orf17, a MutT-type enzyme.
The Escherichia coli Orf17 (NtpA, NudB) protein, a MutT-type enzyme, hydrolyzes oxidized deoxyribonucleotides, including 8-hydroxy-2'-deoxyadenosine 5'-triphosphate and 8-hydroxy-2'-deoxyguanosine 5'-triphosphate, in vitro. To examine its in vivo role(s) in bacteria, plasmid DNAs containing the orf17 gene in the sense and antisense orientations were introduced. When the Orf17 protein was overexpressed in mutT cells, the rpoB mutant frequency was decreased. On the other hand, similar effects were not observed when Orf17 was overexpressed in wild type and orf135 cells. Expression of the antisense RNA of the orf17 gene did not produce an obvious phenotype, such as increased mutant frequency and resistance to ionizing radiation. These results suggest that the role of the Orf17 protein is to back up the MutT function, and to assist in the elimination of 8-hydroxy-2'-deoxyguanosine nucleotides.
Hori
Mika
M
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Asanuma
Taketoshi
T
Inanami
Osamu
O
Kuwabara
Mikinori
M
Harashima
Hideyoshi
H
Kamiya
Hiroyuki
H
D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D005982:Glutathione Transferase / Q000096:biosynthesis; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011755:Pyrophosphatases / Q000096:biosynthesis* / Q000235:genetics; D016372:RNA, Antisense / Q000096:biosynthesis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D000096964:Nudix Hydrolases
D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D029968:Escherichia coli Proteins; D005982:Glutathione Transferase; D011755:Pyrophosphatases; D016372:RNA, Antisense; D011993:Recombinant Fusion Proteins; C546903:NudB protein, E coli; C052211:mutT protein, E coli; C422942:nudix hydrolase Orf135; D000096964:Nudix Hydrolases