Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
J Bacteriol. 2019 Sep 20;201(20). doi: 10.1128/JB.00232-19. Print 2019 Oct 15.
Hfq is an RNA chaperone that serves as a master regulator of bacterial physiology. Here we show that in the opportunistic pathogen , the loss of Hfq can result in a dramatic reduction in growth in a manner that is dependent upon MexT, a transcription regulator that governs antibiotic resistance in this organism. Using a combination of chromatin immunoprecipitation with high-throughput sequencing and transposon insertion sequencing, we identify the MexT-activated genes responsible for mediating the growth defect of mutant cells. These include a newly identified MexT-controlled gene that we call We demonstrate that encodes a small protein that is acutely toxic to wild-type cells when produced ectopically. Furthermore, we show that expression is negatively regulated by Hfq, offering a possible explanation for the growth defect of mutant cells. Finally, we present evidence that the expression of MexT-activated genes is dependent upon GshA, an enzyme involved in the synthesis of glutathione. Our findings suggest that Hfq can influence the growth of by limiting the toxic effects of specific MexT-regulated genes. Moreover, our results identify glutathione to be a factor important for the activity of MexT. Here we show that the conserved RNA chaperone Hfq is important for the growth of the opportunistic pathogen We found that the growth defect of mutant cells is dependent upon the expression of genes that are under the control of the transcription regulator MexT. These include a gene that we refer to as , which we show is negatively regulated by Hfq and encodes a small protein that can be toxic when ectopically produced in wild-type cells. Thus, Hfq can influence the growth of by limiting the toxic effects of MexT-regulated genes, including one encoding a previously unrecognized small protein. We also show that MexT activity depends on an enzyme that synthesizes glutathione.
Hfq 是一种 RNA 伴侣，作为细菌生理学的主要调节剂。在这里，我们表明，在机会性病原体中，Hfq 的缺失会导致生长急剧减少，这种方式依赖于 MexT，MexT 是一种转录调节剂，控制该生物体的抗生素耐药性。我们使用染色质免疫沉淀与高通量测序和转座子插入测序的组合，确定了负责介导 突变细胞生长缺陷的 MexT 激活基因。这些基因包括一个新发现的 MexT 控制基因，我们称之为 我们证明编码一种小蛋白，当异位产生时对野生型细胞具有急性毒性。此外，我们表明 表达受 Hfq 负调控，这为 突变细胞的生长缺陷提供了可能的解释。最后，我们提供了证据表明 MexT 激活基因的表达依赖于 GshA，一种参与谷胱甘肽合成的酶。我们的发现表明，Hfq 可以通过限制特定 MexT 调节基因的毒性作用来影响 的生长。此外，我们的结果表明谷胱甘肽是 MexT 活性的重要因素。在这里，我们表明保守的 RNA 伴侣 Hfq 对机会性病原体 的生长很重要。我们发现 突变细胞的生长缺陷依赖于转录调节剂 MexT 控制的基因的表达。这些基因包括我们称为 的基因，我们表明它受 Hfq 负调控，并编码一种小蛋白，当在野生型细胞中外源产生时可能具有毒性。因此，Hfq 可以通过限制 MexT 调节基因的毒性作用来影响 的生长，包括一个编码以前未识别的小蛋白的基因。我们还表明，MexT 活性依赖于合成谷胱甘肽的酶。
