Genetic diversity of the HpyC1I restriction modification system in Helicobacter pylori
Genetic diversity of the HpyC1I restriction modification system in Helicobacter pylori
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DOI：
10.1016/j.resmic.2006.12.002
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发表时间：
2007-04-01
影响因子：
2.6
通讯作者：
Menard, Armelle
中科院分区：
文献类型：
--
作者：
Lehours, Philippe;Dupouy, Sandrine;Menard, Armelle
幽门螺杆菌是独特的，因为其限制性修饰（R-M）系统的数量和多样性异常高。HpyC 1 IR-M最近被表征，并且含有作为内切核酸酶BccI的同功异构体的内切核酸酶。这种R-M参与粘附胃上皮细胞，这是细菌发病机制中的关键步骤。这一观察结果表明，R-M系统除了保护细菌基因组免受外部DNA的影响外，还具有其他假定的生物学功能。在大量的H. pylori菌株，对BccI消化和测序的敏感性。所得结果支持了该R-M系统在H. pylori基因组中，并建议它是一个祖先系统，在H.幽门螺杆菌的进化遵循以下连续步骤：（1）核酸内切酶基因的失活，随后或伴随有：（2）甲基转移酶基因的失活，然后：（3）永久性丢失，仅留下短的核酸内切酶残基序列。(c)2007年，Elsevier Masson SAS。All rights reserved.
Helicobacter pylori is unique because of the unusually high number and diversity of its restriction modification (R-M) systems. HpyC1I R-M was recently characterized and contains an endonuclease which is an isoschizomer of the endonuclease BccI. This R-M is involved in adherence to gastric epithelial cells, a crucial step in bacterial pathogenesis. This observation illustrates the fact that R-M systems have other putative biological functions in addition to protecting the bacterial genome from external DNA. The genomic diversity of HpyC1I R-M was evaluated more precisely on a large collection of H. pylori strains by PCR, susceptibility to BccI digestion and sequencing. The results obtained support the mechanism of gain and loss of this R-M system in the H. pylori genome, and suggest that it is an ancestral system which gradually disappears during H. pylori evolution, following successive steps: (1) inactivation of the endonuclease gene, followed or accompanied by: (2) inactivation of the methyltransferase genes, and then: (3) definitive loss, leaving only short endonuclease remnant sequences. (c) 2007 Elsevier Masson SAS. All rights reserved.