Abstract:
:The enzyme O6-methylguanine-DNA methyltransferase repairs alkylation-induced DNA damage, O6-methylguanine and O4-methylthymine, the former being formed more frequently. Previously, by means of gene targeting, we generated mice in which alleles for methyltransferase were disrupted. We now use these mouse lines, which are totally deficient in methyltransferase activity, to examine protective effects of the enzyme against tumor formation. In gene-targeted female mice given an i.p. injection of 5 mg/kg of dimethylnitrosamine, a larger number of liver and lung tumors occurred, as compared with normal female mice treated in the same manner. In male mice given a lower dose of carcinogen, the difference between normal and gene-targeted mice was statistically insignificant although more tumors did form in the gene-targeted mice. Methyltransferase apparently afforded protection from nitrosamine-induced tumorigenesis.
journal_name
Carcinogenesisjournal_title
Carcinogenesisauthors
Iwakuma T,Sakumi K,Nakatsuru Y,Kawate H,Igarashi H,Shiraishi A,Tsuzuki T,Ishikawa T,Sekiguchi Mdoi
10.1093/carcin/18.8.1631subject
Has Abstractpub_date
1997-08-01 00:00:00pages
1631-5issue
8eissn
0143-3334issn
1460-2180journal_volume
18pub_type
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