| Autor: |
Saffhill, Roy, Fox, Margaret |
| Zdroj: |
Carcinogenesis; 1980, Vol. 1 Issue 6, p487-493, 7p |
| Abstrakt: |
When Chinese hamster V79A cells are cultured in the presence of O-methyl-[6-H]-thymidine the incorporation of this modified nucleoside into newly synthesised DNA is observed. The radioactivity incorporated has been identified as O-methylthymidine by digesting the DNA to 3'-monophosphates with spleen phosphodiesterase followed by treatment with alkaline phosphatase to give O-methylthymidine as the major radioactive product. The radioactivity associated with the latter co-chromatographs with authentic O-methylthymidine in several chromatographic systems. Once incorporated the modified nucleoside appears to be rapidly removed from the DNA with a half-life of 2-3 h. There is no evidence of demethylation of the O-methylthymidine to give thymidine, in either the culture medium or within the cells once incorporated into DNA. Although the levels of incorporation observed are low, (being only 125 O-methylthymidine residues per 10 thymidine residues at a modified nucleoside concentration of 10M), they may still be relevant as similar levels are apparently produced in the DNA of the cultured cells on treatment with biologically significant doses of carcinogenic alkylating agents. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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