RNA结合蛋白参与RNA的加工、降解，影响其稳定性，在转录后水平调控基因的表达。集胞蓝细菌中的Rbp3蛋白可影响脂肪酸脱饱和酶基因和钠离子泵基因等mRNA水平，通过对膜脂不饱和度和钠离子转运的调节参与决定细胞的盐耐受性。由于Rbp3与其他RNA结合蛋白对转录谱具有完全不同的影响，它对于RNA应存在选择性结合。Rbp3还可以通过结合非编码RNA或其他蛋白作用于某些mRNA。本项目将基于Rbp3调控靶标基因的信息，利用遗传修饰、组学分析、生物分子相互作用测试等方法研究其在mRNA和非编码RNA上识别位点的序列/结构特征以及其他促进特异结合的因子，进一步弄清其生理效应的分子机理。其结果对于蓝细菌转录后调控和抗盐机理的研究具有价值。

RNA-binding proteins are involved in processing and degradation of RNA molecules, affect the stablity of mRNA, therefore regulate gene expression at post-transcriptional level. In Synechcystis sp. PCC 6803, a cyanobacterium, Rbp3 affects the abundance of mRNAs of fatty acyl desaturase genes and the Na+/H+ antiporter gene. By regulating the unsaturation degree of membrane lipids and sodium transport, it is involved in salt tolerance of the cyanobacterium. Because Rbp3 shows completely different effects on transcriptome in comparison to other RNA-binding proteins, its binding to RNA should be selective. Alternatively, Rbp3 may recognize mRNAs with the aid of non-coding RNAs or proteins. In this proposal, we describe the plan to identify its recognition sequences/structures on mRNAs or non-coding RNAs and the cofactors that promote the specific binding, with the aim to further clarify the molecular mechanism that underlies its physiological effects. The investigation will be based on the target mRNA information and employ genetic modifications, transcriptomic analyses and biomolecule interaction measurements. The results will contribute to our understanding of post-transcriptional regulation and salt tolerance in cyanobacteria.