The role of queuosine modification for virulence in Shigella flexneri

Queuosine(Q)是一种高度修饰的7-去氮鸟嘌呤碱基，发现于所选tRNA的摆动位置，它平衡了各自C-末端和U-末端Q-密码子之间的翻译速度。有趣的是，早期的工作表明Q修饰不仅限于tRNAs，而且mRNAs也可能携带这种修饰。具体地说，有人认为福氏志贺氏菌毒力因子的mRNA是Q-修饰的。福氏志贺氏菌是一种在人类中引起志贺氏菌病(痢疾，一种严重形式的腹泻)的致病细菌。基于我们在裂解酵母中对tRNAs的队列糖基化修饰的专业知识，我们将在这里研究这种修饰如何影响福氏志贺氏菌的整体转录和翻译。使用我们为无偏检测Q修饰的RNA而开发的新的Q-RIP-Seq技术，我们将询问福氏志贺氏菌转录组中除tRNA之外的Q修饰的RNA。潜在的靶标将使用突变图谱和直接RNA测序进行进一步研究，并将使用分子生物学和遗传学来确定修饰的功能相关性。此外，我们将调查缺乏队列修饰如何改变该细菌的全球转录和翻译。总之，我们将获得Q修饰如何影响这种细菌中翻译的综合观点，我们将确定这如何控制志贺氏菌的毒力。

Queuosine (Q) is a hypermodified 7-deazaguanine base that is found at the Wobble position of selected tRNAs, and it equilibrates translational speed between the respective C- and U-ending Q-codons. Interestingly, earlier work indicates that Q modification is not restricted to tRNAs, but that mRNAs may also carry this modification. Specifically, it was suggested that the mRNA of a virulence factor in Shigella flexneri is Q-modified. S. flexneri is a pathogenic bacterium that causes shigellosis (dysentery, a severe form of diarrhea) in humans. Based on our expertise in queuosine modification of tRNAs in fission yeast, we here will investigate how this modification affects global transcription and translation in S. flexneri. Using the novel Q-RIP-Seq technology that we developed for the unbiased detection of Q-modified RNAs, we will interrogate the S. flexneri transcriptome for RNAs other than tRNAs that are Q-modified. Potential targets will be further investigated using mutational profiling and direct RNA sequencing, and the functional relevance of the modification will be determined using molecular biology and genetics. Furthermore, we will investigate how the absence of queuosine modification alters global transcription and translation in this bacterium. Altogether, we will thus obtain an integrated view of how Q modification affects translation in this bacterium, and we will determine how this controls virulence in Shigella flexneri.