Nelson M, Burbank D E, Van Etten J L
Megabase Research Products, Lincoln, NE 68504, USA.
Biol Chem. 1998 Apr-May;379(4-5):423-8. doi: 10.1515/bchm.1998.379.4-5.423.
The >320 kb dsDNA genomes of 16 viruses which infect Chlorella strain NC64A and 5 viruses infecting Chlorella strain Pbi were tested for their sensitivity/resistance to more than 80 DNA restriction endonucleases. From the known methylation sensitivities of these enzymes to site-specific 5-methylcytosine and N6-methyladenine DNA modifications, we deduce that the 16 NC64A viruses encode at least 13 different sequence-specific DNA methyltransferases and the 5 Pbi viruses encode at least 7 sequence-specific DNA methyltransferases. Each DNA methyltransferase has a 2 to 4 base pair DNA recognition sequence. Some individual viruses encode as many as ten different DNA methyltransferases, making these chlorella virus genomes among the most concentrated sources of DNA methyltransferase genes known.
对感染小球藻NC64A菌株的16种病毒的大于320 kb双链DNA基因组以及感染小球藻Pbi菌株的5种病毒进行了测试，检测它们对80多种DNA限制性内切酶的敏感性/抗性。根据这些酶对位点特异性5-甲基胞嘧啶和N6-甲基腺嘌呤DNA修饰的已知甲基化敏感性，我们推断16种NC64A病毒编码至少13种不同的序列特异性DNA甲基转移酶，5种Pbi病毒编码至少7种序列特异性DNA甲基转移酶。每种DNA甲基转移酶都有一个2至4个碱基对的DNA识别序列。一些单个病毒编码多达十种不同的DNA甲基转移酶，使这些小球藻病毒基因组成为已知的DNA甲基转移酶基因最集中的来源之一。
