Antibodies against 7-methyldeoxyguanosine: its detection in rat peripheral blood lymphocyte DNA and potential applications to molecular epidemiology.
Polyclonal antibodies have been raised against the imidazole ring-open form of 7-methyldeoxyguanosine (7-mdGua). A combined high performance liquid chromatography/immunoassay method has been developed using these antibodies which provides a specific and sensitive way to quantitate 7-mdGua in DNA. Following enzyme hydrolysis and chromatographic purification of 7-mdGua, the adduct is quantitatively converted to the ring-open form and can be measured at levels as low as 0.05 pmol by immunoassay. With 1 mg of DNA a level below 1 adduct per 10(7) normal deoxynucleosides can be measured. Using DNA modified by radiolabeled carcinogens, a good correlation between 7-mdGua levels, as measured by immunoassay or radioactivity, was obtained. In rats treated with dimethylnitrosamine (0.4 and 1.0 mg/kg), both 7-mdGua and O6-methyldeoxyguanosine were detected in peripheral blood lymphocyte DNA. In addition the levels of both adducts at time points up to 48 h posttreatment were very similar to those seen in liver DNA from the same animals. The measurement of 7-mdGua, quantitatively the major methylation adduct, in small cell samples such as lymphocytes has great potential in determining the exposure of humans to environmental methylating agents such as nitrosamines.
Degan
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Unit of Mechanisms of Carcinogenesis, International Agency for Research on Cancer, Lyon, France.
Montesano
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Wild
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CP
D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000032:analysis* / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D008099:Liver / Q000378:metabolism; D008214:Lymphocytes / Q000032:analysis* / Q000378:metabolism; D008745:Methylation; D051381:Rats
D000906:Antibodies; C048746:7-methyl-2-deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine