蛋白质SUMO化修饰调控植物细胞周期G2/M期转换的分子机制研究

细胞周期的精确调节对植物器官发育至关重要，但关于植物细胞周期G1/S和G2/M检验点调控机制的研究还不够深入。蛋白质SUMO化是一种翻译后修饰，调控底物的亚细胞定位、稳定性或活性等。申请人前期的工作发现拟南芥SUMO连接酶AtMMS21通过影响E2Fa/DPa复合物，调控植物细胞的G1/S期转换。在此基础上发现，AtMMS21也参与G2/M期检验点的调节，但具体机制不明。为了揭示该机制，申请人通过酵母双杂交筛选与AtMMS21相互作用的G2/M转换相关蛋白，发现一个与之互作的转录相关因子，命名为MIG1。本项目将运用生物化学、细胞生物学和遗传学等方法，围绕AtMMS21介导的SUMO化修饰对MIG1功能的影响以及该过程是否通过促进MIG1与其互作因子MAP1的结合以调控G2/M期转换的机制进行研究。本项目将有利于揭示蛋白修饰调控植物细胞周期的机制，也将为后续农作物改良提供依据。

The precise maintenance of cell cycle is critical for plant development, but the regulation mechanisms on the G1/S and G2/M checkpoints remain unclear. SUMOylation is an important type of protein modification regulating the subcellular localization, stability or activity of substrates. The previous study from our laboratory revealed that the Arabidopsis SUMO ligase AtMMS21 regulates G1/S transition by dissociation of the E2Fa/DPa complex. The further analysis suggested that AtMMS21 is also involved in the regulation of G2/M transition via an unknown mechanism. To uncover this mechanism, a yeast two-hybrid screening has been applied to identify the G2/M related factors interacting with AtMMS21. As a result, a transcription related factor named as MIG1 was identified in the assay. In the further study, multiple approaches from biochemistry, cell biology and genetics will be used to investigate the regulation mechanism of MIG1 by the SUMOylation mediated via AtMMS21, as well as the effect of SUMOylation on the MIG1/MAP1 complex. This study will improve our understanding on the function of protein modification in plant cell cycle regulation, and will be interesting for the researchers in plant development and agriculture.