Kirnos M D, Aleksandrushkina N I, Vaniushin B F
Biokhimiia. 1981 Aug;46(8):1458-74.
A method for two-dimensional DEAE-TLC fractionation and a subsequent quantitative spectrophotometric determination of the 5-methylcytosine containing pyrimidine oligodeoxyribonucleotides isolated from plant and animal DNA is proposed. Using this method, the distribution of 5-methylcytosine among pyrimidine oligodeoxyribonucleotides in various plant and animal DNA was studied. It was found that the methylation patterns of DNA in higher plants and animals are quite different, but they are similar among various plants or among different animal DNAs. More than half of the 5-methylcytosine residues in animal DNAs are localized in the monopyrimidine fraction (Pu-C-Pu); however, in plant DNAs there are two types of heavily methylated sequences (Pu-C-Pu and Pu-(CT)-Pu). It is suggested that methylation of plant DNAs occurs in two different sites possessing the second order symmetry with axis lined across the dinucleotide CpG or complementary AT base pair. Possible involvement of eucaryotic DNA-methylases in replicative and reparative DNA synthesis and in hormonal regulation of DNA methylation at and after DNA synthesis in plants and animals as well as a possible role of DNA methylation in regulation of gene activity in tissues and cells are discussed.
提出了一种二维二乙氨基乙基纤维素薄层层析分离法以及随后对从植物和动物DNA中分离出的含5-甲基胞嘧啶的嘧啶寡脱氧核糖核苷酸进行定量分光光度测定的方法。利用该方法，研究了5-甲基胞嘧啶在各种植物和动物DNA的嘧啶寡脱氧核糖核苷酸中的分布情况。结果发现，高等植物和动物DNA的甲基化模式有很大差异，但在不同植物之间或不同动物DNA之间却很相似。动物DNA中超过一半的5-甲基胞嘧啶残基位于单嘧啶部分（嘌呤-胞嘧啶-嘌呤）；然而，在植物DNA中有两种高度甲基化的序列类型（嘌呤-胞嘧啶-嘌呤和嘌呤-（胞嘧啶-胸腺嘧啶）-嘌呤）。有人提出，植物DNA的甲基化发生在两个具有二阶对称性的不同位点，对称轴横跨二核苷酸CpG或互补的AT碱基对。讨论了真核生物DNA甲基化酶可能参与植物和动物DNA复制和修复合成以及DNA合成时和合成后DNA甲基化的激素调节，以及DNA甲基化在组织和细胞基因活性调节中的可能作用。
