Novák Jakub, Jurnečka David, Linhartová Irena, Holubová Jana, Staněk Ondřej, Štipl Daniel, Dienstbier Ana, Večerek Branislav, Azevedo Nayara, Provazník Jan, Beneš Vladimír, Šebo Peter
Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
Laboratory of Post-Transcriptional Control of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
mSystems. 2020 Dec 8;5(6):e00612-20. doi: 10.1128/mSystems.00612-20.
The BvgS/BvgA two-component system controls expression of ∼550 genes of , of which, ∼245 virulence-related genes are positively regulated by the BvgS-phosphorylated transcriptional regulator protein BvgA (BvgA∼P). We found that a single G-to-T nucleotide transversion in the 5'-untranslated region (5'-UTR) of the gene enhanced transcription of the ribosomal protein operon and of the gene and provoked global dysregulation of genome expression. This comprised overproduction of the alpha subunit (RpoA) of the DNA-dependent RNA polymerase, downregulated BvgA and BvgS protein production, and impaired production and secretion of virulence factors by the mutant. Nonetheless, the mutant survived like the parental bacteria for >2 weeks inside infected primary human macrophages and persisted within infected mouse lungs for a longer period than wild-type These observations suggest that downregulation of virulence factor production by bacteria internalized into host cells may enable persistence of the whooping cough agent in the airways. We show that a spontaneous mutation that upregulates transcription of an operon encoding ribosomal proteins and causes overproduction of the downstream-encoded α subunit (RpoA) of RNA polymerase causes global effects on gene expression levels and proteome composition of Nevertheless, the resulting important downregulation of the BvgAS-controlled expression of virulence factors of the whooping cough agent did not compromise its capacity to persist for prolonged periods inside primary human macrophage cells, and it even enhanced its capacity to persist in infected mouse lungs. These observations suggest that the modulation of BvgAS-controlled expression of virulence factors may occur also during natural infections of human airways by and may possibly account for long-term persistence of the pathogen within infected cells of the airways.
BvgS/BvgA双组分系统控制着约550个基因的表达，其中约245个与毒力相关的基因由BvgS磷酸化的转录调节蛋白BvgA（BvgA∼P）正向调控。我们发现，该基因5'非翻译区（5'-UTR）中的单个G到T核苷酸颠换增强了核糖体蛋白操纵子和该基因的转录，并引发了基因组表达的全局失调。这包括DNA依赖性RNA聚合酶的α亚基（RpoA）过量产生、BvgA和BvgS蛋白产生下调，以及突变体毒力因子的产生和分泌受损。尽管如此，该突变体在感染的原代人巨噬细胞内的存活时间与亲本细菌一样超过2周，并且在感染的小鼠肺中持续的时间比野生型更长。这些观察结果表明，内化到宿主细胞中的细菌对毒力因子产生的下调可能使百日咳杆菌能够在气道中持续存在。我们表明，一个上调编码核糖体蛋白的操纵子转录并导致RNA聚合酶下游编码的α亚基（RpoA）过量产生的自发突变，对百日咳杆菌的基因表达水平和蛋白质组组成产生了全局影响。然而，由此导致的百日咳杆菌BvgAS控制的毒力因子表达的重要下调并没有损害其在原代人巨噬细胞内长期持续存在的能力，甚至增强了其在感染小鼠肺中持续存在的能力。这些观察结果表明，在百日咳杆菌对人类气道的自然感染过程中，也可能发生BvgAS控制的毒力因子表达的调节，这可能是该病原体在气道感染细胞内长期持续存在的原因。
