Department of Bioengineering, Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisbon, Portugal.
J Bacteriol. 2013 Aug;195(16):3514-23. doi: 10.1128/JB.00242-13. Epub 2013 May 31.
Burkholderia cenocepacia J2315 is a highly epidemic and transmissible clinical isolate of the Burkholderia cepacia complex (Bcc), a group of bacteria causing life-threatening respiratory infections among cystic fibrosis patients. This work describes the functional analysis of the 136-nucleotide (nt)-long MtvR small noncoding RNA (sRNA) from the Bcc member B. cenocepacia J2315, with homologues restricted to the genus Burkholderia. Bioinformatic target predictions revealed a total of 309 mRNAs to be putative MtvR targets. The mRNA levels corresponding to 17 of 19 selected genes were found to be affected when MtvR was either overexpressed or silenced. Analysis of the interaction between MtvR and the hfq mRNA, one of its targets, showed that the sRNA binds exclusively to the 5' untranslated region (UTR) of the hfq mRNA. This interaction resulted in decreased protein synthesis, suggesting a negative regulatory effect of MtvR on the RNA chaperone Hfq. Bacterial strains with MtvR silenced or overexpressed exhibited pleiotropic phenotypes related to growth and survival after several stresses, swimming and swarming motilities, biofilm formation, resistance to antibiotics, and ability to colonize and kill the nematode Caenorhabditis elegans. Together, the results indicate that the MtvR sRNA is a major posttranscriptional regulator in B. cenocepacia.
洋葱伯克霍尔德菌 J2315 是洋葱伯克霍尔德菌复合体（Bcc）的一种高度流行和可传播的临床分离株，Bcc 是一组导致囊性纤维化患者发生危及生命的呼吸道感染的细菌。本工作描述了来自 Bcc 成员洋葱伯克霍尔德菌 J2315 的 136 个核苷酸（nt）长的 MtvR 小非编码 RNA（sRNA）的功能分析，其同源物仅限于伯克霍尔德菌属。生物信息学靶标预测共预测到 309 个 mRNAs 可能是 MtvR 的靶标。当 MtvR 过表达或沉默时，发现 19 个选定基因中的 17 个基因的 mRNA 水平受到影响。MtvR 与其靶标之一 hfq mRNA 之间相互作用的分析表明，该 sRNA 仅与 hfq mRNA 的 5'非翻译区（UTR）结合。这种相互作用导致蛋白质合成减少，表明 MtvR 对 RNA 伴侣 Hfq 具有负调节作用。沉默或过表达 MtvR 的细菌菌株表现出与多种应激后生长和存活、游泳和群集运动、生物膜形成、抗生素耐药性以及定植和杀死秀丽隐杆线虫有关的表型。总之，这些结果表明 MtvR sRNA 是洋葱伯克霍尔德菌中的一种主要的转录后调控因子。
