蛋白质O-GlcNAc糖基化动态检测新技术的开发及其在早期胚胎发育研究中的应用

O-GlcNAc糖基化是发生于蛋白质丝、苏氨酸残基上的动态可逆的单糖修饰，作为细胞内一种重要的营养感受机制，参与调控信号转导、基因转录、和新陈代谢等众多生物学过程。细胞内O-GlcNAc糖基化的水平由两种互相拮抗的酶OGT和OGA所维持，其动态平衡对胚胎发育至关重要。果蝇和小鼠中OGT的功能缺失引起早期胚胎致死，人类OGT基因突变与小儿智力发育障碍相关。由于针对蛋白质O-GlcNAc糖基化修饰的时空动态检测和干预手段的缺乏，目前对其调控胚胎发育的关键底物和具体分子机制尚不完全明确。本项目拟开发动态标记蛋白质O-GlcNAc糖基化的新方法以及靶向去O-GlcNAc糖基化的新策略，利用这些新手段解析O-GlcNAc糖基化在早期胚胎发育过程中的动态特征和作用机制。该项目将打造一支具有国际影响力的蛋白质O-GlcNAc糖基化的研究队伍，为与此相关的人类重大疾病的诊断和防治提供科学技术储备。

O-GlcNAcylation is a reversible and dynamic process that involves the addition and removal of a single N-acetylglucosamine molecule on Ser/Thr residues of proteins. As a major nutrient sensor in the cell, it regulates many important cellular processes including signal transduction, transcription, epigenetics, and metabolism. Proper O-GlcNAc level, maintained by two opposing enzymes, O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT), is essential for embryonic development. Ogt null Drosophila and mice are embryonic lethal. In human, patients possessing Ogt mutations display shared features, including severe intellectual disability, developmental delay, ataxia, microcephaly, etc. So far, we still don’t know which O-GlcNAcylation events are critical for development and what are the underlying molecular mechanisms, partially due to lack of effective detecting and intervening approaches. Here we propose to develop new methods to precisely label this highly-dynamic posttranslational modification, and to remove O-GlcNAc modifications in a locus-specific manner. We will use these new techniques to dissect the dynamic properties of O-GlcNAcylation and decipher the molecular mechanisms of O-GlcNAc modifications in regulating embryogenesis. We expect that the completion of this research project will build a world-class research team on O-GlcNAcylation, and help us better understand the molecular basis of O-GlcNAc related human diseases.