Genome-wide analysis of chromosomal import patterns after natural transformation of Helicobacter pylori.
Genome-wide analysis of chromosomal import patterns after natural transformation of Helicobacter pylori.
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DOI：
10.1038/ncomms11995
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发表时间：
2016-06-22
影响因子：
16.6
通讯作者：
Suerbaum S
中科院分区：
文献类型：
--
作者：
Bubendorfer S;Krebes J;Yang I;Hage E;Schulz TF;Bahlawane C;Didelot X;Suerbaum S
重组在细菌病原体幽门螺杆菌的进化中起着主导作用，但其动力学仍不完全清楚。在这里，我们使用体外转化系统结合基因组测序来研究自然转化后的染色体整合模式。单个转换周期最多产生21个导入，重复的转换最多产生92个导入（8%的序列替换）。进口长度呈双峰分布，平均长度为28和1,645 bp。对来自慢性感染者的配对幽门螺杆菌基因组的重新分析显示了体内相同的双峰输入模式。受体细菌的限制性内切酶（REases）不能独立于甲基化抑制同源DNA的整合。相反，酶限制了异源DNA的输入。我们得出结论，限制性修饰系统抑制了新序列的基因组整合，但它们对同源重组没有障碍，这与观察到的幽门螺杆菌基因含量的稳定性及其高度重组的群体结构相一致。细菌基因组对外源DNA的吸收和整合在幽门螺杆菌的进化中起着重要作用。在这里，作者描述了染色体整合的双峰模式，并展示了限制性修饰系统如何限制异源DNA的输入。
Recombination plays a dominant role in the evolution of the bacterial pathogen Helicobacter pylori, but its dynamics remain incompletely understood. Here we use an in vitro transformation system combined with genome sequencing to study chromosomal integration patterns after natural transformation. A single transformation cycle results in up to 21 imports, and repeated transformations generate a maximum of 92 imports (8% sequence replacement). Import lengths show a bimodal distribution with averages of 28 and 1,645 bp. Reanalysis of paired H. pylori genomes from chronically infected people demonstrates the same bimodal import pattern in vivo. Restriction endonucleases (REases) of the recipient bacteria fail to inhibit integration of homeologous DNA, independently of methylation. In contrast, REases limit the import of heterologous DNA. We conclude that restriction-modification systems inhibit the genomic integration of novel sequences, while they pose no barrier to homeologous recombination, which reconciles the observed stability of the H. pylori gene content and its highly recombinational population structure. Uptake and integration of exogenous DNA into the bacterial genome play an important role in the evolution of the pathogen Helicobacter pylori. Here, the authors describe a bimodal pattern of chromosomal integration and show how restriction-modification systems limit the import of heterologous DNA.