Role of small proteins in the stress response of alpha-proteobacteria

小蛋白在α-变形菌应激反应中的作用

• 批准号: 379643478
• 负责人: Professorin Dr. Gabriele Klug
• 金额: --
• 依托单位: Institut für Mikrobiologie und Molekularbiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/379643478?language=en
• 关键词: Role; small; proteins; stress; response

This project will elucidate the role of small proteins in the stress response of Alphaproteobacteria. It will initially focus on the small DUF1127 (domain of unknown function) proteins, which are found in many Alpha- and Gammaproteobacteria and are structurally related to domains from eukaryotic RNA binding proteins.The DUF1127 domain comprises 40 amino acids (aa), which either represent almost a complete protein of 45-50 aa or the C-terminal domain of proteins with 60-75 aa, in rare cases up to 100 aa. We will first concentrate on the elucidation of the function of the two DUF1127 proteins RSP_6037 and RSP_0557 in the facultative photosynthetic bacterium Rhodobacter sphaeroides, for which preliminary data are available. RSP_6037 is co-transcribed with 4 sRNAs (CcsR1-4) with a function in singlet oxygen and other stress responses. DUF1127 protein genes often co-localize with genes for CcsR homologs in genomes from Alphaproteobacteria. In R. sphaeroides the sRNAs are generated by RNase E-mediated processing from the primary transcript and the RSP_6037 protein strongly affects their level. The second DUF1127 protein, RSP_0577, is also induced by several stresses, plays a role in stress defense and has a moderate effect on the levels of the CcsR sRNAs. While RSP_6037 is essential, RSP_0557 is not essential and not part of an operon. We want to test the hypothesis that the DUF1127 proteins are RNA binding proteins, which may affect RNA processing. However we will also consider an interaction of DUF1127 proteins to DNA or to other proteins.We will quantify the amount of DUF1127 proteins under different growth conditions, analyze their effect on global RNA levels and define the minimal peptide sequence required for the biological function (collaboration with the Z1 and Z2 projects). We will perform RNA-protein binding studies or, if rather interaction to DNA is confirmed, DNA-protein binding studies and map the binding sites on the transcriptome or genome in collaboration with Z2. Based on the preliminary data the exact mechanisms of function of DUF1127 proteins should be elucidated. We also like to solve the structure of the DUF1127 proteins, also in combination with the ligand, in collaboration with Harald Schwalbe. Later on we will also address the function of DUF 1127 proteins in other Alpha-proteobacteria, preferentially those studied by other members of the priority program. It will be interesting to find out, whether DUF1127 proteins serve a very similar function in different species or whether they can adopt different functions.Since it is highly likely that also other small proteins have important functions in stress responses, we want to identify the peptidome of R. sphaeroides (Z1) in response to singlet oxygen and heat stress. Further small proteins will be selected for functional analysis, preferentially those with homologs detected in other species in course of the priority program.

本计画将阐明小分子蛋白质在α-变形菌的胁迫反应中的角色。它最初将专注于小型DUF 1127 DUF 1127结构域包含40个氨基酸（aa），其代表几乎完整的45-50 aa蛋白质或具有60-75 aa的蛋白质的C-末端结构域，在极少数情况下高达100个AA。我们将首先集中精力阐明兼性光合细菌球形红细菌中两种DUF 1127蛋白RSP_6037和RSP_0557的功能，目前已有初步数据。RSP_6037与4种sRNA（CcsR 1 -4）共转录，在单线态氧和其他应激反应中发挥作用。DUF 1127蛋白基因通常与α变形菌基因组中的CcsR同源物基因共定位。In R. sRNA通过RNase E介导的加工从初级转录物产生，并且RSP_6037蛋白强烈影响它们的水平。第二种DUF 1127蛋白RSP_0577也由几种应激诱导，在应激防御中起作用，并对CcsR sRNA的水平具有中等影响。虽然RSP_6037是必需的，但RSP_0557不是必需的，也不是操纵子的一部分。我们想验证DUF 1127蛋白是RNA结合蛋白的假设，这可能会影响RNA加工。然而，我们也将考虑DUF 1127蛋白质与DNA或其他蛋白质的相互作用。我们将在不同的生长条件下定量DUF 1127蛋白质的量，分析它们对全局RNA水平的影响，并确定生物功能所需的最小肽序列（与Z1和Z2项目合作）。我们将进行RNA-蛋白质结合研究，或者如果证实与DNA的相互作用，则进行DNA-蛋白质结合研究，并与Z2合作绘制转录组或基因组上的结合位点。根据初步的数据，DUF 1127蛋白的确切功能机制应该被阐明。我们还希望与Harald Schwalbe合作解决DUF 1127蛋白质的结构，也与配体结合。稍后，我们还将讨论DUF 1127蛋白在其他α-变形菌中的功能，优先考虑优先计划的其他成员所研究的那些。DUF 1127蛋白在不同的物种中是否具有相似的功能，或者它们是否具有不同的功能，这将是一个有趣的发现，因为其他小蛋白很可能在应激反应中也具有重要的功能，我们希望鉴定R. sphaeroides（Z1）对单线态氧和热胁迫的反应。将选择更多的小蛋白进行功能分析，优先选择那些在优先计划过程中在其他物种中检测到同源物的蛋白。