Membrane-coupled mRNA trafficking in Ustilago maydis

MRNAs的主动转运和局部翻译是精确确定时空蛋白表达的关键。越来越多的证据表明，在信使核糖核酸转运和膜转运之间存在密切联系，包括信使核糖核酸与内质网或内小体的密集共转运。后者是在研究植物病原菌Ustilago maydis侵染菌丝中依赖微管的mRNAs运输时发现的。特别是，Septin mRNA和编码蛋白在穿梭内体上的运输对于极地生长过程中有效的Septin丝状化是必不可少的。在这个项目中，我们将解决膜偶联mRNA转运的两个关键方面。首先，我们的目标是确定在侵染性菌丝的极地生长过程中，mRNA和膜运输之间的新联系。在与研究小组合作伙伴的密切合作下，我们将在哺乳动物细胞、酿酒酵母和梅迪斯酵母中进行比较。我们将研究新发现的膜相关RNA结合蛋白(RBPs)在菌丝生长过程中的作用。我们将结合遗传学、细胞生物学和生化方法对这些限制性商业惯例进行功能分析，并揭示与膜运输以及靶向mRNAs的联系。其次，我们将鉴定和研究内体mRNA运输机制的新组件的功能。为此，我们将以关键的RBP Rrm4为诱饵，在这个真菌模式生物中建立和应用一种体内邻近依赖的标记方法。在该研究小组的框架内，我们将重点研究运输所需的相关限制性商业惯例或调节因素，例如，促进Rrm4的RNA结合能力。综上所述，这些概述的实验将对膜运输和RNA运输如何从机械上联系起来提供新的见解。我们希望发现在进化中保守的新细胞生物学概念。

Active transport and local translation of mRNAs are essential to precisely determine spatiotemporal protein expression. Evidence is accumulating that there is an intimate link between mRNA transport and membrane trafficking, including an intensive co-transport of mRNAs with ER or endosomes. The latter was discovered studying microtubule-dependent transport of mRNAs in infectious hyphae of the plant pathogen Ustilago maydis. In particular, transport of septin mRNA and encoded protein on shuttling endosomes is essential for efficient septin filamentation during polar growth. In this project, we will address two key aspects of membrane-coupled mRNA trafficking. Firstly, we aim to identify novel links between mRNA and membrane trafficking during polar growth of infectious hyphae. In close collaboration with partners of the research group we will perform a comparative approach in mammalian cells, Saccharomyces cerevisiae and U. maydis. Our part will be to study the role of newly identified membrane-associated RNA-binding proteins (RBPs) during hyphal growth. We will combine genetic, cell biological and biochemical approaches for functional analysis of these RBPs and uncover the link to membrane trafficking as well as target mRNAs. Secondly, we will identify and study the function of novel components of the endosomal mRNA transport machinery. To this end, we will establish and apply an in vivo proximity-dependent labelling approach in this fungal model organism using the key RBP Rrm4 as bait. In the framework of this research group, we will focus on associated RBPs needed for transport or regulatory factors that, e.g., promote the RNA-binding capacity of Rrm4. Together, the outlined experiments will yield new insight into how membrane trafficking and RNA transport are mechanistically linked. We expect to uncover new cell biological concepts conserved in evolution.