Distribution of open reading frames of plasticity region of strain J99 in Helicobacter pylori strains isolated from gastric carcinoma and gastritis patients in Costa Rica
Distribution of open reading frames of plasticity region of strain J99 in Helicobacter pylori strains isolated from gastric carcinoma and gastritis patients in Costa Rica
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DOI：
10.1128/iai.68.11.6240-6249.2000
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发表时间：
2000-11-01
影响因子：
3.1
通讯作者：
Mégraud, F
中科院分区：
文献类型：
--
作者：
Occhialini, A;Marais, A;Mégraud, F
幽门螺杆菌（Helicobacter pylori，J 99）的可塑性区域是一个含有33个菌株特异性开放阅读框（open reading frames，ORF）的染色体大片段，具有致病岛的特征。为了研究该基因可塑性区域的多样性，我们将可塑性区域内20个开放阅读框和其边界上2个开放阅读框的22个探针与临床分离的H. pylori的杂交图谱具有高度变异性。大多数临床菌株呈现与J 99相似的杂交谱;因此，这些ORF不是J 99菌株特异性的。没有发现特定的杂交模式和菌株的临床来源之间的关联。然而，两个单一的ORF（JHP 940和JHP 947）更可能在胃癌株中发现。它们可能是新的致病性标记。还在不同条件下对J 99菌株进行了这些ORF的体外表达研究。13个ORF一致表达，6个一致关闭，3个差异表达。组成型表达基因大多位于可塑性区域的3'端。我们的研究结果表明，可塑性区域，而不是被认为是一个致病性岛本身，应被认为是一个基因组岛，这代表了一个大片段的外源DNA整合到基因组中，并不一定牵连的菌株的致病能力。
The plasticity region of Helicobacter pylori strain J99 is a large chromosomal segment containing 33 strain-specific open reading frames (ORFs) with characteristics of a pathogenicity island. To study the diversity of the plasticity region, 22 probes corresponding to 20 ORFs inside the plasticity region and two ORFs on its boundaries were hybridized to genomic DNA isolated from clinical strains of H. pylori from patients with gastritis or gastric adenocarcinoma, Highly variable hybridization patterns were observed. The majority of the clinical strains presented a hybridization profile similar to that of J99; thus, these ORFs are not J99 strain specific. No association was found between a particular hybridization pattern and the clinical origin of the strain. Nevertheless, two single ORFs (JHP940 and JHP947) were more likely to be found in gastric cancer strains. They may be new pathogenicity markers. An in vitro expression study of these ORFs was also performed for the J99 strain, under different conditions. Thirteen ORFs were consistently expressed, six were consistently shut off and three were expressed differentially. Most of the constitutionally expressed genes were located on the 3' part of the plasticity region. Our results show that the plasticity region, rather than being considered a pathogenicity island per se, should be considered a genomic island, which represents a large fragment of foreign DNA integrated into the genome and not necessarily implicated in the pathogenic capacity of the strain.