CLONING, CHARACTERIZATION, AND EXPRESSION IN ESCHERICHIA-COLI OF THE GENE CODING FOR THE CPG DNA METHYLASE FROM SPIROPLASMA SP STRAIN MQ1(M.SSSL)
CLONING, CHARACTERIZATION, AND EXPRESSION IN ESCHERICHIA-COLI OF THE GENE CODING FOR THE CPG DNA METHYLASE FROM SPIROPLASMA SP STRAIN MQ1(M.SSSL)
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DOI：
10.1093/nar/18.5.1145
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发表时间：
1990-03-11
影响因子：
14.9
通讯作者：
RAZIN, A
中科院分区：
文献类型：
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作者：
RENBAUM, P;ABRAHAMOVE, D;RAZIN, A
本文介绍了螺旋体DNA甲基酶基因的克隆、鉴定及其在大肠杆菌中的表达。菌株MQ1(M.cntdo.)SSSL)。这种酶完全且唯一地甲基化CpG序列(1)。螺旋体基因是利用其自身的启动子在大肠杆菌中转录的。整个信息的翻译需要使用蛋白石抑制子，这表明UGA三联体编码螺旋体中的色氨酸。对该基因的序列分析显示，在一个1158bp的开放阅读框中有几个UGA三联体。推导的氨基酸序列显示在M.cntdot中。SSSL细菌胞嘧啶DNA甲基酶的所有共同结构域。推定的序列识别结构域的m.cntdo.SSIL与小鼠DNA甲基化酶没有明显的相似性，尽管它们具有共同的序列特异性。该克隆的酶在体内和体外都对CpG序列进行了特异性甲基化。与哺乳动物的酶不同，哺乳动物的酶主要是一种维持甲基酶，M.cntdo.SSIL具有原核胞嘧啶DNA甲基酶的从头活性。
We describe here the cloning, characterization and expression in E. coli of the gene coding for a DNA methylase from Spiroplasma sp. strain MQ1 (M .cntdot. Sssl). This enzyme methylates completely and exclusively CpG sequences (1). The Spiroplasma gene was transcribed in E. coli using its own promoter. Translation of the entire message required the use of an opal suppressor, suggesting that UGA triplets code for tryptophan in Spiroplasma. Sequence analysis of the gene revealed several UGA triplets, in a 1158 bp long open reading frame. The deduced amino acid sequence revealed in M .cntdot. Sssl all common domains characteristic of bacterial cytosine DNA methylases. The putative sequence recognition domain of M .cntdot. Sssl showed no obvious similarities with that of the mouse DNA methylase, in spite of their common sequence specificity. The cloned enzyme methylated exclusively CpG sequences both in vivo and in vitro. In contrast to the mammalian enzyme which is primarily a maintenance methylase, M .cntdot. Sssl displayed de novo methylase activity, characteristic of prokaryotic cytosine DNA methylases.