The role of queuosine modification for virulence in Shigella flexneri

肌苷（Q）是一种高度修饰的7-脱氮鸟嘌呤碱基，存在于选定的tRNA的摆动位置，它平衡了相应的C-和U-末端Q-密码子之间的翻译速度。有趣的是，早期的研究表明Q修饰并不局限于tRNA，mRNA也可能携带这种修饰。特别是，有人建议，在福氏志贺菌的毒力因子的mRNA是Q-修饰。S.弗氏菌是一种致病菌，可引起人类志贺菌病（痢疾，一种严重的腹泻）。 基于我们在裂殖酵母中tRNA的腺苷修饰方面的专业知识，我们在这里将研究这种修饰如何影响S.弗氏杆菌属使用我们开发的用于无偏检测Q修饰RNA的新型Q-RIP-Seq技术，我们将询问S。针对Q修饰的tRNA以外的RNA的弗氏转录组。将使用突变谱和直接RNA测序进一步研究潜在的靶点，并使用分子生物学和遗传学确定修饰的功能相关性。此外，我们将研究如何在这种细菌中，腺苷修饰的情况下改变全局转录和翻译。总而言之，我们将获得Q修饰如何影响该细菌翻译的综合观点，并确定这如何控制福氏志贺氏菌的毒力。

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.