Bogdarina I G, Bur'ianov Ia I, Baev A A
Biokhimiia. 1982 Nov;47(11):1831-4.
The distribution of 5-methylcytosine in Eco RI-Bam HI fragments of phage lambda DNA in vitro methylated by Eco RII methylase has been studied. The general picture of distribution of methylated sites in phage lambda DNA is slightly different from the statistical distribution. However, the sites have been found, where the distribution of 5-methylcytosine is not accidental. A complete absence of 5-methylcytosine in the J-fragment, a genome lambda area essential for site-specific recombination, has been found. The absence of Eco RII is supposed to be the best protection of this area of phage genome from the increased mutagenesis, characteristic for nucleotide sequences methylated by DNA-methylated Eco RII and Eco RII type.
研究了经Eco RII甲基化酶体外甲基化的噬菌体λDNA的Eco RI - Bam HI片段中5 - 甲基胞嘧啶的分布情况。噬菌体λDNA中甲基化位点的总体分布情况与统计分布略有不同。然而，已发现存在一些位点，其中5 - 甲基胞嘧啶的分布并非偶然。在J片段（噬菌体基因组中位点特异性重组所必需的区域）中完全没有发现5 - 甲基胞嘧啶。推测缺少Eco RII是噬菌体基因组该区域免受因DNA甲基化的Eco RII和Eco RII类型甲基化的核苷酸序列所特有的诱变增加影响的最佳保护方式。
