The plant splicing code: regulatory components and functions in developmental processes

选择性剪接（AS）从一种前体mRNA产生信使RNA （mRNA）变体，从而大量增加转录组多样性。AS广泛存在于植物中，已被证明响应多种信号而发生变化，并参与关键的生理过程，如昼夜节律、开花时间控制和种子萌发。此外，最近在植物中发现了第一个全球AS调节因子。尽管取得了这一重要进展，但AS在植物发育和胁迫反应中的实际作用范围仍然是开放的，剪接密码（剪接因子和mRNA基序的相互作用网络）的功能尚不清楚。我们之前的工作发现拟南芥中的多嘧啶束结合蛋白（pptbs）是as的关键调控因子，并揭示了与植物发育和抗旱性的不同方面的重要联系。在这里提出的项目中，ptb介导的AS控制的顺式调控元件将被定义，ptb与其他来自丝氨酸/精氨酸富（SR）蛋白和异质核糖核蛋白（hnRNP）蛋白家族的剪接因子的相互作用将被表征。此外，还将进一步阐明pbs在植物发育和非生物胁迫响应中的作用，并分析关键AS事件或协同AS程序对这些复杂生物过程的可能贡献。这项工作旨在解码植物剪接代码的关键组成部分，并为模式系统拟南芥中这种基因调控机制的功能含义提供新的见解。基于先前的研究结果，表明AS参与了基本的发育转变和其他农业相关性状，如抗旱性，这项工作也有望为作物育种和工程转化研究的新方法奠定基础。

Alternative splicing (AS) generates messenger RNA (mRNA) variants from one type of precursor mRNA and thereby massively increases transcriptome diversity. Being widespread in plants, AS has been demonstrated to change in response to diverse signals and to be involved in critical physiological processes, such as circadian rhythms, flowering time control, and seed germination. Furthermore, first global regulators of AS have recently been identified in plants. Despite this important progress, the actual scope of AS in plant development and stress responses remains open and functioning of the splicing code, an interaction network of splicing factors and mRNA motifs, is unknown. Our previous work identified Polypyrimidine tract binding proteins (PTBs) from Arabidopsis thaliana as critical regulators of AS and revealed important links to different aspects of plant development and drought tolerance. In the project proposed here, cis-regulatory elements of PTB-mediated AS control will be defined and the interplay of PTBs with other splicing factors from the families of Serine/Arginine-rich (SR) proteins and heterogeneous ribonucleoprotein (hnRNP) proteins will be characterized. Additionally, the role of PTBs in plant development and abiotic stress responses will be further elucidated, and the possible contribution of key AS events or concerted AS programs to these complex biological processes will be analyzed. This work aims at decoding critical components of the plant splicing code and at providing novel insights into the functional implications of this gene regulatory mechanism in the model system A. thaliana. Based on previous findings indicating the involvement of AS in fundamental developmental transitions and other agriculturally relevant traits such as drought tolerance, this work is also expected to lay the foundations for novel approaches in translational research in crop breeding and engineering.