期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：7
页码：2725-2728
DOI：10.1073/pnas.74.7.2725
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The content of 5-methylcytosine in eukaryotic DNA was measured by mass spectrometry. Almost equal amounts of methylated cytosine were found in the DNA of various tissues of the chicken. When chromatin or nuclei were digested with micrococcal nuclease, 50% of the DNA was found to be nuclease resistant. In contrast to this, over 75% of the 5-methylcytosine was protected from nuclease digestion by chromatin proteins. These results suggest that 5-methylcytosine is nonrandomly distributed with respect to the nucleoproteins.
