人工设计PPR蛋白靶向修饰水稻线粒体基因

PPR蛋白是高等植物特有的一类单链RNA结合蛋白，参与细胞器RNA转录后加工的多个过程，如RNA编辑、RNA切割、mRNA稳定性等。基于其独特的序列重复特性，研究者提出了一个PPR基序识别一个碱基的“识别密码”，从而打开了人工设计PPR蛋白的大门。本研究以水稻为研究对象，通过分析水稻中P型PPR蛋白人工设计了7个靶向水稻线粒体基因的PPR蛋白，并对其功能和靶标基因的功能进行研究。前期研究结果显示：aOsPPR1能够特异性地结合其靶标RNA，并且定位于线粒体。转基因植株基因表达分析显示aOsPPR1出现了高表达，靶标nad1基因的表达量也有不同程度的升高，甚至部分植株出现了RNA切割现象。本项目拟进一步对其余几个人工设计PPR蛋白展开功能研究，以揭示更多的水稻线粒体基因功能。同时对细胞器RNA转录后修饰系统进行建模，开发线粒体基因表达调控的新方法，为创建具有抗逆功能的新型农作物提供技术支撑。

PPR protein is a type of single-stranded RNA binding protein specifically occurs in higher plants, which involves in multiple processes of organellar RNA post-transcription, such as RNA editing, RNA cleavage, and mRNA stability. According to its unique sequence repetition characteristics, researchers have proposed a "recognition code" for one PPR motif to one nucleotide correspondence, and thereby open the door to artificial design of PPR protein. Our study took rice as the research object, by analyzing the P-type PPR proteins in rice, seven PPR proteins that targeted to rice mitochondrial genes were artificially designed, both of their function and the corresponding target function studies have been conducted. Our previous studies have shown that aOsPPR1 can specifically bind to its target RNA and localize to mitochondria. Gene expression analysis of transgenic plants showed that aOsPPR1 was highly expressed, the expression of target nad1 gene also increased to varying degrees, and even some transgenic lines showed RNA cleavage. This project intends to further investigate the function of several other artificially designed PPR proteins to reveal more rice mitochondrial gene functions. While, we will model organellar RNA post-transcriptional modification system, and develop new methods of mitochondrial gene expression regulation and provide technical support for the creation of new type of crops that can adapt to various terrible environments.