Expression, maturation and turnover of DrrS, an unusually stable, DosR regulated small RNA in Mycobacterium tuberculosis.
Expression, maturation and turnover of DrrS, an unusually stable, DosR regulated small RNA in Mycobacterium tuberculosis.
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DOI：
10.1371/journal.pone.0174079
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Arnvig KB
中科院分区：
文献类型：
--
作者：
Moores A;Riesco AB;Schwenk S;Arnvig KB
结核分枝杆菌依赖于对一系列宿主环境中遇到的压力进行调整的能力，而这种调整需要基因表达发生重大变化。小RNA(SRNAs)作为原核生物基因表达的转录后调节因子发挥着重要作用，它们与胁迫反应有关，对于病原体来说，它们与宿主环境的适应有关。尽管如此，对结核分枝杆菌RNA生物学的了解仍然有限。在这里，我们使用与DosR相关的sRNA作为例子来研究分枝杆菌RNA生物学的多个方面，这些方面可能适用于其他结核分枝杆菌的sRNA和mRNAs。我们发现，随着细胞进入稳定期，这种特殊的sRNA的积累是缓慢的，但却是强大的。利用报告基因分析，我们发现SRNA核心启动子被DosR激活，我们将SRNA DRRs重新命名为DosR调节的SRNA。此外，我们发现DRRs被转录为更长的前体DRRS+，它被快速加工成成熟的和高度稳定的DRRs。我们首次在分枝杆菌中描述了与这种非凡稳定性有关的RNA结构决定因素，并展示了几个核苷酸的添加如何导致严重的不稳定。最后，我们展示了这种RNA元件如何增强异源基因的表达。因此，该元件以及其不稳定的衍生物可能被用来结合不同的启动子变体在转录后调节分枝杆菌的基因表达。此外，我们的发现将有助于进一步研究分枝杆菌RNA生物学这一严重不足的主题，以及调节性RNA在结核分枝杆菌发病机制中所起的作用。
Mycobacterium tuberculosis depends on the ability to adjust to stresses encountered in a range of host environments, adjustments that require significant changes in gene expression. Small RNAs (sRNAs) play an important role as post-transcriptional regulators of prokaryotic gene expression, where they are associated with stress responses and, in the case of pathogens, adaptation to the host environment. In spite of this, the understanding of M. tuberculosis RNA biology remains limited. Here we have used a DosR-associated sRNA as an example to investigate multiple aspects of mycobacterial RNA biology that are likely to apply to other M. tuberculosis sRNAs and mRNAs. We have found that accumulation of this particular sRNA is slow but robust as cells enter stationary phase. Using reporter gene assays, we find that the sRNA core promoter is activated by DosR, and we have renamed the sRNA DrrS for DosR Regulated sRNA. Moreover, we show that DrrS is transcribed as a longer precursor, DrrS+, which is rapidly processed to the mature and highly stable DrrS. We characterise, for the first time in mycobacteria, an RNA structural determinant involved in this extraordinary stability and we show how the addition of a few nucleotides can lead to acute destabilisation. Finally, we show how this RNA element can enhance expression of a heterologous gene. Thus, the element, as well as its destabilising derivatives may be employed to post-transcriptionally regulate gene expression in mycobacteria in combination with different promoter variants. Moreover, our findings will facilitate further investigations into the severely understudied topic of mycobacterial RNA biology and into the role that regulatory RNA plays in M. tuberculosis pathogenesis.