Rodríguez-Valverde Diana, León-Montes Nancy, Siqueiros-Cendón Tania, Rivera-Gutiérrez Sandra, Ares Miguel A, De la Cruz Miguel A
Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico.
J Med Microbiol. 2023 Apr;72(4). doi: 10.1099/jmm.0.001682.
Enterotoxigenic (ETEC) strains produce at least one of two types of enterotoxins: the heat-labile (LT) and heat-stable (ST) toxins, which are responsible for the watery secretory diarrhoea that is a hallmark of the human ETEC infection. One regulatory system that controls the transcription of virulence genes in pathogenic bacteria is the CpxRA two-component system (TCS). We reported that the bicistronic operon, which encodes for the A and B subunits of LT, was repressed for the CpxRA TCS by direct binding of CpxR-P from -12 to +6 bp with respect to the transcription start site of . Moreover, the Cpx-response activation down-regulated the transcription of genes, and this negative effect was CpxRA-dependent. Our data show that CpxRA TCS is a negative regulator of the LT, one of the main virulence determinants of ETEC.
产肠毒素大肠杆菌（ETEC）菌株产生两种肠毒素中的至少一种：不耐热（LT）毒素和耐热（ST）毒素，它们是导致水样分泌性腹泻的原因，而水样分泌性腹泻是人类ETEC感染的一个标志。一种控制致病细菌毒力基因转录的调节系统是CpxRA双组分系统（TCS）。我们报道，编码LT A和B亚基的双顺反子操纵子，被CpxR-P从相对于转录起始位点的-12至+6 bp处直接结合而被CpxRA TCS抑制。此外，Cpx反应激活下调了基因的转录，并且这种负面影响是CpxRA依赖性的。我们的数据表明，CpxRA TCS是LT的负调节因子，LT是ETEC的主要毒力决定因素之一。
