RNA-binding landscape of Rrm4, a key RNA-binding protein mediating mRNA transport in Ustilago maydis

rna结合蛋白是转录后基因调控的关键因子。通常，它们包含多个rna结合域，用于与目标mrna相互作用。rna结合蛋白介导的一个关键过程是mrna沿微管的长距离运输。这在高度极化的细胞中尤其重要，如哺乳动物神经元或真菌菌丝。揭示这些rna结合蛋白精确功能的一个重要方法是在转录组水平上鉴定靶mrna和结合位点。最近，我们发现含有三个RNA识别基序的RNA结合蛋白Rrm4是调控植物病原真菌黑穗病菌侵染菌丝微管依赖性mRNA转运的主要因子。在这里，我们应用了一种改进的iCLIP方法，体内UV交联和免疫沉淀，以转录组范围和单核苷酸分辨率识别靶mrna和结合位点。关键发现将在非原生条件下使用异源系统或体外方法进行验证。此外，我们将探讨Rrm4是否具有调控mRNA加工、稳定性或翻译等全局功能。获得的结果将为真核rna结合蛋白调节mRNA转运的相互作用提供新的见解。

RNA-binding proteins are key factors of posttranscriptional gene regulation. Commonly, they contain more than one RNA-binding domain for interaction with target mRNAs. A key process mediated by RNA-binding proteins is long-distance transport of mRNAs along microtubules. This is particularly important in highly polarized cells such as mammalian neurons or fungal hyphae. An important approach to uncover the precise function of these RNA-binding proteins is the identification of target mRNAs and binding sites at the transcriptome-wide level. Recently, we showed that the RNA-binding protein Rrm4 containing three RNA recognition motifs is the major factor regulating microtubule-dependent mRNA transport in infectious hyphae of the plant pathogenic fungus Ustilago maydis. Here, we apply an improved iCLIP approach, in vivo UV crosslinking and immune precipitation, to identify target mRNAs and binding sites transcriptome-wide and at single nucleotide resolution. Key findings will be verified under non-native conditions using heterologous systems or in vitro approaches. Furthermore, we will address whether Rrm4 carries out global functions such as regulating mRNA processing, stability or translation. The obtained results will provide new insights into the interaction of eukaryotic RNA-binding proteins regulating mRNA transport.