Participation of two sRNA RyhB homologs from the fish pathogen Yersinia ruckeri in bacterial physiology
Participation of two sRNA RyhB homologs from the fish pathogen Yersinia ruckeri in bacterial physiology
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DOI：
10.1016/j.micres.2020.126629
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发表时间：
2021-01-01
影响因子：
6.7
通讯作者：
Calderon, Ivan L.
中科院分区：
文献类型：
--
作者：
Acuna, Lillian G.;Jose Barros, M.;Calderon, Ivan L.
小分子非编码RNA（Small noncoding RNAs，sRNAs）是细菌基因表达和生理的重要调控因子。RyhB是一种铁响应性sRNA，在大肠杆菌中有很好的特征，在其他肠杆菌科中保守。在这项研究中，我们确定和表征两个RyhB同源物（命名为RyhB-1和RyhB-2）的鱼类病原体鲁氏耶尔森氏菌。我们发现，在其他肠杆菌科，RyhB-1和RyhB-2诱导铁饥饿下，抑制的毛皮调节，并依赖于Hfq的稳定性。尽管在表达上存在这些相似性，但Y.缺乏RyhB-1（Δ ryhB-1）或RyhB-2（Δ ryhB-2）的ruckeri表现出不同的表型。与野生型相比，Delta ryhB-1菌株在细菌培养物中显示出高运动表型、减少的生物膜形成、增加的复制速率、更快的生长和增加的ATP水平。相比之下，在鲑鱼细胞培养物中，Delta ryhB-1菌株表现出增加的存活率。另一方面，与野生型相比，Delta ryhB-2菌株是非运动的，并且显示出增强的生物膜形成。通过定量RT-PCR在铁耗尽培养基中培养的野生型、Delta ryhB-1、Delta ryhB-2和Delta ryhB-1 Delta ryhB-2菌株中分析了从不同细菌物种中选择的RyhB保守靶标子集的表达。RyhB-1对大多数分析基因（sodB、acnA、sdhC、bfr、fliF等）的表达产生负面影响，这些基因的功能与代谢和运动有关，涉及含铁蛋白。在分析的基因中，只有sdhC和bfr作为RyhB-2的靶基因出现。综上所述，这些结果表明Y. ruckeri RyhB同源物以非冗余作用参与细菌生理学的调节。
Small noncoding RNAs (sRNAs) are important regulators of gene expression and physiology in bacteria. RyhB is an iron-responsive sRNA well characterized in Escherichia coli and conserved in other Enterobacteriaceae. In this study, we identified and characterized two RyhB homologs (named RyhB-1 and RyhB-2) in the fish pathogen Yersinia ruckeri. We found that, as in other Enterobacteriaceae, both RyhB-1 and RyhB-2 are induced under iron starvation, repressed by the Fur regulator, and depend on Hfq for stability. Despite these similarities in expression, the mutant strains of Y. ruckeri lacking RyhB-1 (Delta ryhB-1) or RyhB-2 (Delta ryhB-2) exhibited differential phenotypes. In comparison with the wild type, the Delta ryhB-1 strain showed a hypermotile phenotype, reduced biofilm formation, increased replication rate, faster growth, and increased ATP levels in bacterial cultures. By contrast, in salmon cell cultures, the Delta ryhB-1 strain exhibited an increased survival. On the other hand, the Delta ryhB-2 strain was non-motile and showed augmented biofilm formation as compared to the wild type. The expression of a subset of RyhB conserved targets, selected from different bacterial species, was analyzed by quantitative RT-PCR in wild type, Delta ryhB-1, Delta ryhB-2, and Delta ryhB-1 Delta ryhB-2 strains cultured in iron-depleted media. RyhB-1 negatively affected the expression of most analyzed genes (sodB, acnA, sdhC, bfr, fliF, among others), whose functions are related to metabolism and motility, involving iron-containing proteins. Among the genes analyzed, only sdhC and bfr appeared as targets for RyhB-2. Taken together, these results indicate that Y. ruckeri RyhB homologs participate in the modulation of the bacterial physiology with non-redundant roles.