Silencing of natural transformation by an RNA chaperone and a multitarget small RNA
Silencing of natural transformation by an RNA chaperone and a multitarget small RNA
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DOI：
10.1073/pnas.1601626113
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发表时间：
2016-08-02
影响因子：
11.1
通讯作者：
Charpentier, Xavier
中科院分区：
文献类型：
--
作者：
Attaiech, Laetitia;Boughammoura, Aida;Charpentier, Xavier
高度保守的DNA摄取系统允许许多细菌主动输入和整合外源DNA。这一过程被称为自然转化，代表了水平基因转移（HGT）的主要机制，涉及毒力和抗生素抗性决定因素的获得。尽管有HGT的证据和编码DNA摄取系统的基因的高度保守性，但大多数细菌物种在实验室条件下似乎是不可转化的。在自然可转化的物种中，DNA摄取系统仅在细菌进入称为感受态的生理状态时表达，该状态在特定条件下发展。在这里，我们调查的机制，控制在人类病原体嗜肺军团菌的DNA摄取系统的表达。我们发现，该系统的阻遏物显示一个保守的ProQ/FinO结构域，并与一个新的特点是反式作用的sRNA，RocR相互作用。它们一起靶向编码DNA摄取系统的基因的mRNA，以控制自然转化。这种基于RNA的沉默代表了以前未知的控制HGT这一主要机制的调控手段。重要的是，这些发现还表明，染色体编码的ProQ/FinO结构域蛋白可以帮助反式作用的sRNA，这类RNA伴侣可以在整个细菌物种的转录后基因调控中发挥关键作用。
A highly conserved DNA uptake system allows many bacteria to actively import and integrate exogenous DNA. This process, called natural transformation, represents a major mechanism of horizontal gene transfer (HGT) involved in the acquisition of virulence and antibiotic resistance determinants. Despite evidence of HGT and the high level of conservation of the genes coding the DNA uptake system, most bacterial species appear non-transformable under laboratory conditions. In naturally transformable species, the DNA uptake system is only expressed when bacteria enter a physiological state called competence, which develops under specific conditions. Here, we investigated the mechanism that controls expression of the DNA uptake system in the human pathogen Legionella pneumophila. We found that a repressor of this system displays a conserved ProQ/FinO domain and interacts with a newly characterized trans-acting sRNA, RocR. Together, they target mRNAs of the genes coding the DNA uptake system to control natural transformation. This RNA-based silencing represents a previously unknown regulatory means to control this major mechanism of HGT. Importantly, these findings also show that chromosome-encoded ProQ/FinO domain-containing proteins can assist trans-acting sRNAs and that this class of RNA chaperones could play key roles in post-transcriptional gene regulation throughout bacterial species.