ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Direct measurements of the methylation of newly-synthesized DNA were made in cultures of a clonal mouse adrenal cortex cell line, Y129OS3, by (1) following the incorporation of radioactivity from methionine-(methyl)-C14 into a segment of DNA which had been density-labeled with bromouracil and (2) labeling DNA cytosine with C14-deoxycytidine and then following the appearance of radioactivity in DNA 5-methylcytosine. The results establish that during exponential growth the DNA of this cell line is methylated entirely within a few minutes of its synthesis. Using the second technique described above accurate, sensitive measurements of DNA methylation levels can be made by comparing radioactivity in 5-methylcytosine to radioactivity in cytosine plus 5-methylcytosine. In this cell line 5-methylcytosine accounts for 4.3 ± 0.2% of the DNA cytosine. Some apparent contradictions between these results and those of other workers are discussed.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1040750104
