IDENTIFICATION AND MOLECULAR ANALYSIS OF A LOCUS THAT REGULATES EXTRACELLULAR TOXIN PRODUCTION IN CLOSTRIDIUM-PERFRINGENS
IDENTIFICATION AND MOLECULAR ANALYSIS OF A LOCUS THAT REGULATES EXTRACELLULAR TOXIN PRODUCTION IN CLOSTRIDIUM-PERFRINGENS
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DOI：
10.1111/j.1365-2958.1994.tb01063.x
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发表时间：
1994-06-01
影响因子：
3.6
通讯作者：
ROOD, JI
中科院分区：
文献类型：
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作者：
LYRISTIS, M;BRYANT, AE;ROOD, JI
厌氧细菌产气荚膜梭菌通过产生许多细胞外毒素和酶来介导梭菌性肌坏死或气性坏疽。用转座子Tn916诱变C.在一些实施方案中，产气荚膜梭菌产生降低水平的磷脂酶C、蛋白酶和唾液酸酶，并且不产生任何可检测的产气荚膜梭菌溶素0活性。Southern杂交结果表明，Tn916基因插入到C.产气荚膜杆菌染色体。从野生型菌株中克隆了一个跨越Tn916插入位点的4.3kb Pst Ⅰ片段。当亚克隆到穿梭载体中并导入C.在产气荚膜杆菌中，该片段能够补充Tn916衍生的突变。用含有2.7kb HindIII片段或4.3kb PstI片段的质粒转化突变体，导致毒素和酶水平大于或等于野生型菌株的水平。Pst I片段进行测序，发现可能编码7个开放阅读框架，其中两个似乎是安排在一个操纵子和共享的序列相似性与成员的双组分信号转导系统。推定的virR基因编码的蛋白质的推导分子量为30140，并与序列相似的激活剂的反应调节蛋白质家族。下一个基因，virS，其中Tn916已插入，被预测编码的跨膜蛋白的推导分子量为51274。推定的VirS蛋白的传感器蛋白的序列相似性，也包含一个组氨酸残基的传感器蛋白的组氨酸蛋白激酶家族中高度保守的。使用小鼠模型进行的毒力研究表明，virS基因在组织毒性C.产气荚膜杆菌感染得出的结论是，一个双组分传感器调节系统，激活了一些细胞外毒素和酶参与毒力的表达已被克隆和测序。一个描述C.构建了产气荚膜梭菌。
The anaerobic bacterium Clostridium perfringens mediates clostridial myonecrosis, or gas gangrene, by producing a number of extracellular toxins and enzymes. Transposon mutagenesis with Tn916 was used to isolate a pleiotropic mutant of C. perfringens that produced reduced levels of phospholipase C, protease and sialidase, and did not produce any detectable perfringolysin 0 activity. Southern hybridization revealed that a single copy of Tn916 had inserted into a 2.7 kb HindIII fragment in the C. perfringens chromosome. A 4.3kb PstI fragment, which spanned the Tn916 insertion site, was cloned from the wild-type strain. When subcloned into a shuttle vector and introduced into C. perfringens this fragment was able to complement the Tn916-derived mutation. Transformation of the mutant with plasmids containing the 2.7kb HindIII fragment, or the 4.3kb PstI fragment, resulted in toxin and enzyme levels greater than or equal to those of the wild-type strain. The PstI fragment was sequenced and found to potentially encode seven open reading frames, two of which appeared to be arranged in an operon and shared sequence similarity with members of two-component signal transduction systems. The putative virR gene encoded a protein with a deduced molecular weight of 30140, and with sequence similarity to activators in the response regulator family of proteins. The next gene, virS, into which Tn916 had inserted, was predicted to encode a membrane-spanning protein with a deduced molecular weight of 51274. The putative VirS protein had sequence similarity to sensor proteins and also contained a histidine residue highly conserved in the histidine protein kinase family of sensor proteins. Virulence studies carried out using a mouse model implicated the virS gene in the pathogenesis of histotoxic C. perfringens infections. It was concluded that a two-component sensor regulator system that activated the expression of a number of extracellular toxins and enzymes involved in virulence had been cloned and sequenced. A model that described the regulation of extracellular toxin production in C. perfringens was constructed.