Changes in DNA methyltransferase induced by treatment with N-2-acetylaminofluorene.
We have compared the levels of DNA methyltransferases from rat liver and spleen in both sexes following a single injection of N-2-acetylaminofluorene (AAF). Enzyme extracts from treated animals were obtained at different intervals (2-34 days) after treatment. The extracts were assayed in the presence of chicken erythrocyte DNA and S-adenosyl-L-[Me-3H]methionine. A 55% increase in male rat-liver methyltransferase activity measured by Me-3H incorporation into DNA occurred on day 14. By contrast, female methyltransferase after a similar period revealed a 33% decrease in activity. Between days 21 and 34, there is a progressive return to normal methyltransferase levels. Spleen-derived enzyme studied between days 7 and 14, showed a decrease in methylating activity in both sexes. After replacing corn seed oil by ethanol as the vehicle for AAF injection, we observed a change in liver methyltransferase 48 h after injection. Quantification of radioactive eluates in m5C fractions together with the increase in the integrated area identified as m5C in HPLC chromatograms allowed positive identification of methylated products.
Bravo
L M
LM
Departamento de Quimica y Bioquimica, Facultad de Ciencia, Universidad de Santiago, Chile.
Salas
C E
CE
D015073:2-Acetylaminofluorene / Q000494:pharmacology*; D000818:Animals; D002645:Chickens; D004247:DNA / Q000097:blood; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000096:biosynthesis*; D004790:Enzyme Induction; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000378:metabolism; D013154:Spleen / Q000187:drug effects / Q000201:enzymology*
D012436:S-Adenosylmethionine; D004247:DNA; D015073:2-Acetylaminofluorene; D004248:DNA (Cytosine-5-)-Methyltransferases