Giraud Caroline, Hausmann Stéphane, Lemeille Sylvain, Prados Julien, Redder Peter, Linder Patrick
a Department of Microbiology and Molecular Medicine ; Medical Faculty; University of Geneva ; Michel Servet , Geneva , Switzerland.
RNA Biol. 2015;12(6):658-74. doi: 10.1080/15476286.2015.1035505.
Staphylococcus aureus is a versatile opportunistic pathogen that adapts readily to a variety of different growth conditions. This adaptation requires a rapid regulation of gene expression including the control of mRNA abundance. The CshA DEAD-box RNA helicase was previously shown to be required for efficient turnover of the agr quorum sensing mRNA. Here we show by transcriptome-wide RNA sequencing and microarray analyses that CshA is required for the degradation of bulk mRNA. Moreover a subset of mRNAs is significantly stabilised in absence of CshA. Deletion of the C-terminal extension affects RNA turnover similar to the full deletion of the cshA gene. In accordance with RNA decay data, the C-terminal region of CshA is required for an RNA-independent interaction with components of the RNA degradation machinery. The C-terminal truncation of CshA reduces its ATPase activity and this reduction cannot be compensated at high RNA concentrations. Finally, the deletion of the C-terminal extension does affect growth at low temperatures, but to a significantly lesser degree than the full deletion, indicating that the core of the helicase can assume a partial function and opening the possibility that CshA is involved in different cellular processes.
金黄色葡萄球菌是一种适应性很强的机会致病菌，能够轻松适应各种不同的生长条件。这种适应需要对基因表达进行快速调控，包括对mRNA丰度的控制。先前已证明CshA DEAD盒RNA解旋酶是群体感应mRNA高效周转所必需的。在这里，我们通过全转录组RNA测序和微阵列分析表明，CshA是大量mRNA降解所必需的。此外，在缺乏CshA的情况下，一部分mRNA会显著稳定。C端延伸的缺失对RNA周转的影响与cshA基因的完全缺失相似。根据RNA衰变数据，CshA的C端区域是与RNA降解机制的成分进行RNA非依赖性相互作用所必需的。CshA的C端截短会降低其ATP酶活性，并且这种降低在高RNA浓度下无法得到补偿。最后，C端延伸的缺失确实会影响低温下的生长，但程度明显小于完全缺失，这表明解旋酶的核心可以发挥部分功能，并开启了CshA参与不同细胞过程的可能性。
