拟南芥SKIP基因5'非翻译区对基因表达的调控作用及其分子机制研究

植物通过转录及转录后水平精确调控基因表达从而协调生长发育与响应环境变化。酵母和动物中发现5'UTR通过转录后水平调控基因表达，影响mRNA的稳定性、运输以及翻译效率等过程，然而植物中5'UTR调控基因表达及其机制研究非常有限。申请人前期研究表明拟南芥SKIP通过蛋白剂量效应调控植物生长发育，SKIP通过直接结合自身前体mRNA调控5'UTR内部内含子的可变剪切，SKIP功能降低或缺失产生保留内含子的SKIP 5'UTR，而保留内含子的5'UTR能够抑制自身mRNA的翻译过程。本项目将在上述结果基础上继续通过鉴定SKIP 5'UTR中的调控元件以及互作蛋白，以期解析植物中SKIP 5'UTR调控自身基因表达的分子机制，这将为植物中5'UTR在转录后水平调控基因表达机制提供新认识；同时将有助于理解SKIP通过调控自身5'UTR的可变剪接实现其蛋白水平的精确调控，进而协调植物生长发育与环境适应。

As sessile organisms, plants have to keep the balance between developmental processes and response to environmental changes by regulating gene expression at both transcriptional and post-transcriptional levels. In yeast and animals, it is found that the 5' untranslated regions (5'UTRs) play crucial roles in the regulation of gene expression by the modulation of the mRNA stability, transport, and translation efficiency at post-transcriptional level. However, the biological function and molecular mechanism of 5'UTRs in plants is largely unknown. Our previous studies revealed that AtSKIP regulates plant development processes in a dose-dependent manner. SKIP regulates the alternative splicing of its own 5'UTR by directly binding to its pre-mRNA. Decrease in SKIP activity or loss function of SKIP generated SKIP mRNA that retained the intron in its 5'UTR, and the 5'UTR with the intron retention inhibits protein translation process. The proposed work will further investigate the function and molecular mechanism of SKIP 5'UTR in regulating SKIP expression at post-transcriptional level by identifying the key RNA regulatory element in 5'UTR and its interaction partner. Therefore, the results from the proposed work will provide novel insight into our understanding both the mechanism that 5'UTR regulates gene expression at post-transcriptional level, and the the mechanism that SKIP balances developmental processes and environmental fitness in plants by regulating its own protein level via the regulation of 5'UTR alternative splicing.