组蛋白H2B单泛素化修饰对植物内源生长素稳态的影响和作用机理

生长素是重要的植物激素，调节许多重要的生长发育和生理响应过程。植物体内的生长素水平主要取决于生物合成和代谢两方面的动态平衡，形成复杂的代谢和调控网络。植物体内存在多条生长素合成途径，目前对植物内源生长素稳态平衡及调控机理的了解还很少。前期通过正向遗传学方法筛选分离得到若干生长素缺陷突变体，其中ckrw2（cytokinin induced root waving 2）突变体表现典型的低生长素表型。CKRW2蛋白为一个含有C3HC4锌指结构域的E3泛素连接酶，能对组蛋白H2B进行单泛素化修饰，从而影响生长素合成/代谢和响应等相关基因的转录。目前国内外尚未有组蛋白H2B单泛素化修饰影响植物内源生长素稳态及其响应的报导，本项目拟对组蛋白H2B单泛素化修饰在维持拟南芥内源生长素稳态的作用和机理进行研究。

Auxin is the first discovered plant hormone and controls almost every aspects of plant growth and development. Auxin levels within the plant is primarily determined by the balance between its biosynthesis and metabolism. There are multiple pathways for auxin biosynthesis and metabolism, forming a complex web, for which we are still far from forming a clear picture. We previously isolated an auxin-deficient mutant ckrw2 (cytokinin induced root waving 2), and the CKRW2 gene encodes an C3HC4-RING finger E3 ubiquitin ligase functioning for the H2B monoubiquitination, which usually plays roles in transcriptional regulation. The aim of this project is to study the molecular mechanism of CKRW2 in maintaining auxin homoeostasis and its responses.