Coynault C, Robbe-Saule V, Popoff M Y, Norel F
Institut Pasteur, Unité INSERM 199, Paris, France.
Microb Pathog. 1992 Aug;13(2):133-43. doi: 10.1016/0882-4010(92)90073-w.
The 90 kb virulence plasmid of Salmonella typhimurium is required for bacterial growth beyond the small intestine to deeper tissues such as the spleen and liver of orally inoculated mice. We constructed transcriptional lacZ fusions within the cloned plasmid-borne virulence genes spvA, spvB and spvC of S. typhimurium to demonstrate that spvR encodes a trans-acting positive regulator for the transcription of spvA, spvB and spvC. Data suggesting that the activation of spvABC transcription is dependent on the growth phase of both S. typhimurium and Escherichia coli grown in Luria Broth (LB) are also presented. Complementation experiments for virulence in mice confirmed that at least spvR and spvC are virulence genes and further suggested that the spvRABC gene cluster consists of at least three transcriptional units containing spvR, spvC and spvABC, respectively. Reinitiation of transcription at spvC was confirmed in vitro, using a lacZ fusion, and was shown to be independent of SpvR-mediated control in LB.
鼠伤寒沙门氏菌的90 kb毒力质粒是细菌在口服接种小鼠体内从小肠生长到更深组织（如脾脏和肝脏）所必需的。我们构建了鼠伤寒沙门氏菌克隆质粒携带的毒力基因spvA、spvB和spvC内的转录lacZ融合体，以证明spvR编码spvA、spvB和spvC转录的反式作用正调控因子。还给出了表明spvABC转录激活依赖于在Luria肉汤（LB）中生长的鼠伤寒沙门氏菌和大肠杆菌生长阶段的数据。小鼠毒力互补实验证实，至少spvR和spvC是毒力基因，并进一步表明spvRABC基因簇至少由三个分别包含spvR、spvC和spvABC的转录单元组成。使用lacZ融合体在体外证实了spvC处转录的重新起始，并表明其在LB中独立于SpvR介导的调控。
