Age and strain dependence of O6-methylguanine DNA methyltransferase activity in mice.
The activity of the DNA repair protein O6-methylguanine DNA methyltransferase (MT) was compared in liver extracts from female ICR and male C57BL/6 mice at various ages (3-130 weeks old). Similar patterns of overall enzyme activity were observed in both strains with O6-MT activity being relatively low in young mice (3 or 8 weeks old). However, the activity significantly increased after adolescence (middle age), thereafter decreasing with old age (over 100 weeks old) to a level equivalent to that found in young mice. In an additional strain difference study, O6-MT activities in liver extracts from 4 strains of mice were compared at 5 and 30 weeks of age. Although a similar age-associated increase of enzyme activity in adolescence was confirmed in all 4 strains investigated, the closed-colony ICR mice differed from the inbred strains in demonstrating significantly higher levels of O6-MT activity in females than in males. However, the same tendency was also observed in a comparison of the sexes in 30-week-old C3H/HeN, C57BL/6 and BALB/c mice.
Nakatsuru
Y
Y
Department of Experimental Pathology, Cancer Institute, Tokyo, Japan.
Aoki
K
K
Ishikawa
T
T
D000375:Aging; D000818:Animals; D004260:DNA Repair; D005260:Female; D008099:Liver / Q000201:enzymology / Q000254:growth & development*; D008297:Male; D008780:Methyltransferases / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C / Q000254:growth & development; D008809:Mice, Inbred C3H / Q000254:growth & development; D008810:Mice, Inbred C57BL / Q000254:growth & development; D008813:Mice, Inbred ICR / Q000254:growth & development; D008815:Mice, Inbred Strains / Q000254:growth & development*; D019853:O(6)-Methylguanine-DNA Methyltransferase; D013045:Species Specificity
D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase