Methylation of deoxycytidine in replicating cells treated with ultraviolet radiation and chemical carcinogens
5-Methyl-2'-deoxycytidine (m5dC) levels were measured in DNA from three types of cultured cells following treatment with u.v. radiation and two chemical carcinogens, N-methyl-N-nitrosourea (MNU) and N-acetoxy-2-acetylaminofluorene (NA-AAF). Control values for m5dC in Raji cells (a human lymphoblastoid cell line), S49 cells (a mouse thymic lymphoma cell line) and human diploid fibroblasts are 3.6%, 3.6% and 3.2%, respectively. None of the damaging agents produced a detectable change in methylation levels of newly replicated DNA, even at levels of damage that inhibited replication by 95%. In contrast, treatment with 5-aza-2'-deoxycytidine, a known methyltransferase inhibitor, transiently reduced genomic methylation by 89% and 74% in Raji and S49 cells, respectively. Although other investigators have found a marked reduction in m5dC in DNA replicated after carcinogen treatment, our experiments indicate that extensive demethylation is not a necessary consequence of DNA damage.
- Research Organization:
- Washington University School of Medicine, Department of Pathology, St. Louis, MO
- OSTI ID:
- 6440369
- Journal Information:
- Carcinogenesis (N.Y.); (United States), Journal Name: Carcinogenesis (N.Y.); (United States) Vol. 5:9; ISSN CRNGD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
AROMATICS
AZINES
BIOLOGICAL EFFECTS
CELL CULTURES
CHEMICAL REACTIONS
CONDENSED AROMATICS
DEOXYCYTIDINE
DNA
ELECTROMAGNETIC RADIATION
FLUORENE
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
METHYLATION
NITROSO COMPOUNDS
NITROSOUREAS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATIONS
RIBOSIDES
SOMATIC CELLS
TUMOR CELLS
ULTRAVIOLET RADIATION