Leskinen Katarzyna, Pajunen Maria I, Varjosalo Markku, Fernández-Carrasco Helena, Bengoechea José A, Skurnik Mikael
Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, Finland.
Institute of Biotechnology, University of Helsinki.
Mol Microbiol. 2017 Mar;103(6):1065-1091. doi: 10.1111/mmi.13610. Epub 2017 Jan 23.
In bacteria, the RNA chaperone Hfq enables pairing of small regulatory RNAs with their target mRNAs and therefore is a key player of post-transcriptional regulation network. As a global regulator, Hfq is engaged in the adaptation to external environment, regulation of metabolism and bacterial virulence. In this study we used RNA-sequencing and quantitative proteomics (LC-MS/MS) to elucidate the role of this chaperone in the physiology and virulence of Yersinia enterocolitica serotype O:3. This global approach revealed the profound impact of Hfq on gene and protein expression. Furthermore, the role of Hfq in the cell morphology, metabolism, cell wall integrity, resistance to external stresses and pathogenicity was evaluated. Importantly, our results revealed that several alterations typical for the hfq-negative phenotype were due to derepression of the transcriptional factor RovM. The overexpression of RovM caused by the loss of Hfq chaperone resulted in extended growth defect, alterations in the lipid A structure, motility and biofilm formation defects, as well as changes in mannitol utilization. Furthermore, in Y. enterocolitica RovM only in the presence of Hfq affected the abundance of RpoS. Finally, the impact of hfq and rovM mutations on the virulence was assessed in the mouse infection model.
在细菌中，RNA伴侣蛋白Hfq能使小调控RNA与其靶标mRNA配对，因此是转录后调控网络的关键参与者。作为一种全局调节因子，Hfq参与细菌对外部环境的适应、代谢调控及细菌毒力的调节。在本研究中，我们利用RNA测序和定量蛋白质组学（液相色谱-串联质谱法，LC-MS/MS）来阐明这种伴侣蛋白在肠炎耶尔森菌O:3血清型的生理和毒力中的作用。这种全局分析方法揭示了Hfq对基因和蛋白质表达的深远影响。此外，我们还评估了Hfq在细胞形态、代谢、细胞壁完整性、对外界应激的抗性及致病性方面的作用。重要的是，我们的结果表明，hfq阴性表型的几种典型变化是由于转录因子RovM的去阻遏所致。Hfq伴侣蛋白缺失导致的RovM过表达，造成了生长缺陷延长、脂多糖A结构改变、运动性和生物膜形成缺陷，以及甘露醇利用的变化。此外，在肠炎耶尔森菌中，只有在存在Hfq的情况下，RovM才会影响RpoS的丰度。最后，我们在小鼠感染模型中评估了hfq和rovM突变对毒力的影响。
