Institute of Microbiology v.v.i., Laboratory of post-transcriptional control of gene expression, 14220 Prague, Czech Republic.
Institute for Theoretical Chemistry, University of Vienna, A-1090 Vienna, Austria.
RNA. 2018 Nov;24(11):1530-1541. doi: 10.1261/rna.067306.118. Epub 2018 Aug 10.
is the causative agent of human whooping cough, a highly contagious respiratory disease which despite vaccination programs remains the major cause of infant morbidity and mortality. The requirement of the RNA chaperone Hfq for virulence of suggested that Hfq-dependent small regulatory RNAs are involved in the modulation of gene expression. High-throughput RNA sequencing revealed hundreds of putative noncoding RNAs including the RgtA sRNA. Abundance of RgtA is strongly decreased in the absence of the Hfq protein and its expression is modulated by the activities of the two-component regulatory system BvgAS and another response regulator RisA. Whereas RgtA levels were elevated under modulatory conditions or in the absence of genes, deletion of the gene completely abolished RgtA expression. Profiling of the Δ mutant in the genetic background identified the gene encoding a periplasmic amino acid-binding protein of an ABC transporter as a possible target gene. The results of site-directed mutagenesis and in silico analysis indicate that RgtA base-pairs with the region upstream of the start codon of the mRNA and thereby weakens the BP3831 protein production. Furthermore, our data suggest that the function of the BP3831 protein is related to transport of glutamate, an important metabolite in the physiology. We propose that the BvgAS/RisA interplay regulates the expression of RgtA which upon infection, when glutamate might be scarce, attenuates translation of the glutamate transporter and thereby assists in adaptation of the pathogen to other sources of energy.
百日咳博德特氏菌是人类百日咳的病原体，是一种高度传染性的呼吸道疾病，尽管有疫苗接种计划，但它仍是婴儿发病率和死亡率的主要原因。RNA 伴侣蛋白 Hfq 对毒力的要求表明，Hfq 依赖性小调控 RNA 参与了基因表达的调节。高通量 RNA 测序揭示了数百种假定的非编码 RNA，包括 RgtA sRNA。在缺乏 Hfq 蛋白的情况下，RgtA 的丰度强烈降低，其表达受双组分调节系统 BvgAS 和另一个响应调节因子 RisA 的活性调节。虽然在调节条件下或在没有 基因的情况下，RgtA 水平升高，但 删除 基因完全消除了 RgtA 的表达。在 遗传背景下对 Δ 突变体进行分析，确定了编码 ABC 转运体周质氨基酸结合蛋白的 基因可能是靶基因。定点突变和计算机分析的结果表明，RgtA 与起始密码子上游的区域碱基配对 mRNA，从而削弱了 BP3831 蛋白的产生。此外，我们的数据表明，BP3831 蛋白的功能与谷氨酸的运输有关，谷氨酸是 生理中的一种重要代谢物。我们提出，BvgAS/RisA 相互作用调节 RgtA 的表达，当感染时，当谷氨酸可能稀缺时，它会减弱谷氨酸转运体的翻译，从而有助于病原体适应其他能量来源。
