幽门螺杆菌基因组在CATG位点被hpyIM的产物修饰。
The Helicobacter pylori genome is modified at CATG by the product of hpyIM.
作者信息
Xu Q, Peek R M, Miller G G, Blaser M J
机构信息
Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
出版信息
J Bacteriol. 1997 Nov;179(21):6807-15. doi: 10.1128/jb.179.21.6807-6815.1997.
To understand mechanisms of DNA methylation in Helicobacter pylori, a human pathogen associated with peptic ulcer disease and gastric adenocarcinoma, we cloned a putative DNA methyltransferase gene, hpyIM. This gene contains a 990-bp open reading frame encoding a 329-amino-acid protein, M.HpyI. Sequence analysis revealed that M.HpyI was closely related to CATG-recognizing adenine DNA methyltransferases, including M.NlaIII in N. lactamica. hpyIM was present in all H. pylori strains tested. DNA from wild-type H. pylori strains was resistant to digestion by SphI and NlaIII, which recognize DNA at sites containing CATG, whereas their isogenic hpyIM mutants were susceptible, indicating lack of modification. Overexpression of hpyIM in Escherichia coli rendered DNA from these cells resistant to NlaIII digestion, confirming the role of hpyIM in modifying CATG sites. We conclude that hpyIM encodes a DNA methyltransferase, M.HpyI, that is well conserved among diverse H. pylori strains and that modifies H. pylori genomes at CATG sites.
为了解与消化性溃疡疾病和胃腺癌相关的人类病原体幽门螺杆菌中DNA甲基化的机制，我们克隆了一个假定的DNA甲基转移酶基因hpyIM。该基因包含一个990 bp的开放阅读框，编码一种329个氨基酸的蛋白质M.HpyI。序列分析表明，M.HpyI与识别CATG的腺嘌呤DNA甲基转移酶密切相关，包括乳酸奈瑟菌中的M.NlaIII。hpyIM存在于所有测试的幽门螺杆菌菌株中。来自野生型幽门螺杆菌菌株的DNA对SphI和NlaIII消化具有抗性，SphI和NlaIII在含有CATG的位点识别DNA，而它们的同基因hpyIM突变体则敏感，表明缺乏修饰。hpyIM在大肠杆菌中的过表达使这些细胞的DNA对NlaIII消化具有抗性，证实了hpyIM在修饰CATG位点中的作用。我们得出结论，hpyIM编码一种DNA甲基转移酶M.HpyI，它在不同的幽门螺杆菌菌株中高度保守，并在CATG位点修饰幽门螺杆菌基因组。
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