Small proteins implicated in the virulence of the enteric pathogen Yersinia pseudotuberculosis

肠道病原菌假结核耶尔森菌已经进化出大量不同的致病因子，促进其在哺乳动物宿主中的存活和增殖。到目前为止，已经发现了许多常见的和物种特有的毒力策略，但它们的协调和时空表达和功能仍不完全清楚。最近的发现表明，存在可能参与这些过程的小蛋白。我们最近对假结核耶尔森菌在三种不同毒力相关条件下生长的核糖体图谱(Ribo-seq)/RNA-Seq进行了分析，发现在耶尔森氏菌毒力质粒上编码的小蛋白(21-60aa)有14个短开放阅读框(SORF)。该质粒编码一个III型分泌系统(T3SS)，它将效应蛋白(YOPs)注入宿主固有免疫细胞，以防止通过吞噬消除耶尔森菌。已鉴定的sORF分为三类：(I)与耶尔森氏菌毒力质粒拷贝数有关的小蛋白候选；(Ii)影响T3SS/Yop机制的主要转录激活因子LcrF表达的小蛋白；以及(Iii)影响Yop效应器分泌的小蛋白。已确定的候选基因的一个子集，被预测会影响这些不同毒力相关功能之一，已经被选择和验证，并被证明影响YOP蛋白的合成和/或分泌。基于这些结果，我们在本项目中的主要任务是阐明它们的调节或调节机制，它们的分子功能，相互作用伙伴，细胞定位，以及它们在发病中的作用。

The enteric pathogen Yersinia pseudotuberculosis has evolved a plethora of different pathogenicity factors, which promote survival and proliferation in its mammalian hosts. Until today, many common and species-specific virulence strategies have been discovered but their coordinated and spatiotemporal expression and function is still not fully understood. Recent discoveries made evident that small proteins exist that might participate in these processes. Our recent ribosome profiling (Ribo-seq)/RNA-Seq of Y. pseudotuberculosis, grown under three different virulence-relevant conditions, revealed 14 expressed short open reading frames (sORFs) for small proteins (21-60 aa) encoded on the Yersinia virulence plasmid. This plasmid encodes a type III secretion system (T3SS) that injects effector proteins (Yops) into host innate immune cells to prevent the elimination of Yersinia by phagocytosis. The identified sORFs fall in three different categories: (i) small protein candidates implicated in the copy number of the Yersinia virulence plasmid, (ii) small proteins affecting the expression of the major transcriptional activator LcrF of the T3SS/Yop machinery, and (iii) small proteins affecting the secretion of the Yop effectors. A subset of the identified candidates, which are predicted to influence one of these different virulence-relevant functions, has been selected, validated and shown to influence the synthesis and/or secretion of the Yop proteins. Based on these results our main tasks in this project are to elucidate their regulation or regulatory mechanisms, their molecular function, interaction partners, cellular localization, and their role in pathogenesis.