The 5-Methylcytosine in DNA of Rats

Abstract

The GC content and amount of 5-methylcytosine (5-MeCyt) have been determined in total DNA from certain organs of male albino rats 1, 12 and 28 months of age. A marked tissue specificity of DNA with respect to the 5-MeCyt content has been revealed. The 5-MeCyt content in DNA decreases with age in the brain, heart and spleen; it does not change in the liver and lungs and slightly increases in the kidneys. There are no other age differences in the DNA studied (GC content, T<sub>m</sub> and other physico-chemical properties). Thus, age differences in the 5-MeCyt content are most probably due to the different level of DNA methylation. The 5-MeCyt content in liver DNA changes drastically under the influence of hydrocortisone and other gene inducers. These changes are tissue specific and positively correlate with the functional activity of cells. The changes in the DNA methylation under the action of hormones resemble those appearing with age. DNA methylation may be one of the regulatory mechanisms of gene activity and the changes in 5-MeCyt content observed may be somehow responsible for the process of ageing.

Keywords

Affiliated Institutions

• Moscow State University TJ
• Lomonosov Moscow State University RU

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