Regulated expression of Clostridium perfringens enterotoxin in naturally cpe-negative type A, B, and C isolates of C-perfringens
Regulated expression of Clostridium perfringens enterotoxin in naturally cpe-negative type A, B, and C isolates of C-perfringens
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DOI：
10.1128/iai.64.8.3301-3309.1996
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发表时间：
1996-08-01
影响因子：
3.1
通讯作者：
McClane, BA
中科院分区：
文献类型：
--
作者：
Czeczulin, JR;Collie, RE;McClane, BA
产气荚膜梭菌肠毒素 (CPE) 是导致 A 型产气荚膜梭菌食物中毒相关症状的毒力因子，是由产肠毒素 A 型产气荚膜梭菌分离物在胃肠道中形成孢子时产生的。全球产气荚膜梭菌种群中不到 5% 的产气荚膜梭菌明显携带 cpe 基因。当转化为天然 cpe 阴性产气荚膜杆菌食物中毒分离株时，产气荚膜杆菌食物中毒分离株可以表达并适当调节（即，以孢子形成相关的方式表达）。当携带 5.7 kb DNA 插入片段（含有 cpe 开放阅读框加上来自产气荚膜梭菌食物中毒分离株 NCTC 8239 的上游和下游库序列各大于 1 kb）或 1.6 kb 插入片段（仅含有 NCTC 8239 的 cpe 开放阅读框）的低拷贝数质粒电穿孔到 cpe 阴性 C、产气荚膜杆菌 A 型中时，观察到孢子形成相关的 CPE 表达。 B 和 C 分离株，Northern (RNA) 印迹分析表明，转化体和天然产肠毒素产气荚膜梭菌 NCTC 8239 中的 cpe 信息大小相似，并且该信息仅在转化体或 NCTC 8239 的孢子形成培养物中可检测到。这些研究强烈表明，许多（如果不是全部）cpe 阴性产气荚膜杆菌分离株（包括 B 型分离株，目前尚不清楚它们是否天然表达 CPE）产生参与产气荚膜梭菌食物中毒分离株的 CPE 表达的正常（即孢子形成相关）转录调节的因子。这些发现与 CPE 调节因子也调节产气荚膜梭菌中其他基因的表达一致。
Clostridium perfringens enterotoxin (CPE), the virulence factor responsible for symptoms associated with C. perfringens type A food poisoning, is produced by enterotoxigenic C. perfringens type A isolates when these bacteria sporulate in the gastrointestinal tract, Less than 5% of the global C, perfringens population apparently carries the cpe gene, To assess the distribution of cpe-regulatory factors, we investigated whether the cpe gene of a C. perfingens food poisoning isolate can be expressed and properly regulated (i.e., expressed in a sporulation-associated manner) when transformed into naturally cpe-negative C. perfringens isolates. Sporulation-associated CPE expression was observed when low-copy-number plasmids carrying either a 5.7-kb DNA insert, containing the cpe open reading frame plus >1 kb each of upstream and downstream banking sequences from C. perfringens food poisoning isolate NCTC 8239, or a 1.6-kb insert, containing only the cpe open reading frame of NCTC 8239, were electroporated into cpe-negative C, perfringens type A, B, and C isolates, Northern (RNA) blot analysis demonstrated that the sizes of the cpe message in the transformants and the naturally enterotoxigenic C. perfringens NCTC 8239 were similar and that this message was detectable only in sporulating cultures of the transformants or NCTC 8239, These studies strongly suggest that many, if not all, cpe-negative C. perfringens isolates (including type B isolates, which are not known to naturally express CPE) produce a factor(s) involved in normal (i.e., sporulation-associated) transcriptional regulation of CPE expression by C. perfringens food poisoning isolates. These findings are consistent with this CPE-regulatory factor(s) also regulating the expression of other genes in C. perfringens.