锌指蛋白ZC4H2调控神经系统发育的分子机制

The ZC4H2 gene on the X chromosome encodes a small Zinc finger factor. In human, mutations of ZC4H2 cause severe developmental defects, including global developmental delay, fetal akinesia, intellectual disability, and Arthrogryposis Multiplex Congenita. In a zebrafish model, knockout of ZC4H2 led to specific loss of ventral interneurons in the spinal cord. However, the function of ZC4H2 remains unknown. We have recently identified RNF220, an ubiquitin E3 ligase, as a key regulator of spinal neural patterning through regulation of Gli, the transcriptional effector of Shh signaling. In a yeast two-hybrid screen and following experiments, we found that ZC4H2 can bind and stabilize RNF220. In zebrafish models, we confirmed that loss of ZC4H2 and RNF220 yielded similar interneuron loss in the ventral spinal cord and that they interact genetically, supporting that ZC4H2 likely works through the RNF220-Gli path to regulate neural patterning. RNF220 is also involved in the development of locus coeruleus, a nucleus in the pons of the brainstem , which is the principal site for brain synthesis of norepinephrine. We have created a ZC4H2 conditional knockout mouse model, and found that locus coeruleus was also lost in the ZC4H2 knockout mouse embryos. In this project, we will analyze in detail the roles of ZC4H2 in neural development using both zebrafish and mouse models, and dissect the molecular mechanisms involved in its regulation of RNF220 and Gli signaling. This study would provide novel insights in neural patterning and ZC4H2 deficiency.

ZC4H2编码一种锌指蛋白，其突变与神经发育缺陷包括发育迟缓、智力障碍、运动能力低下等相关，但其作用机制尚不清楚。近期，我们鉴定了一个泛素连接酶RNF220，可通过对Shh信号通路等的调控参与脊髓、脑干、小脑等的发育。通过酵母双杂交等实验，我们发现ZC4H2可结合并稳定RNF220。我们构建了RNF220和ZC4H2敲除的斑马鱼和小鼠模型，初步分析表明，二者表现出相似的神经发育缺陷，提示ZC4H2正是通过RNF220参与神经发育调控的。本研究将系统分析ZC4H2敲除小鼠、斑马鱼胚胎神经系统发育表型与ZC4H2-RNF220的遗传互作,解析ZC4H2通过RNF220调控神经图式形成和脑干发育的分子机制。本研究将全面揭示ZC4H2缺陷的致病机理，为ZC4H2缺陷病人的诊断与治疗提供依据。

ZC4H2编码一种锌指蛋白，其突变与神经发育缺陷包括发育迟缓、智力障碍、运动能力低下等相关。本研究利用ZC4H2敲除小鼠、斑马鱼等模型，通过遗传学、分子细胞生物学方法系统解析了ZC4H2 通过调节泛素连接酶RNF220的稳定性及其与靶蛋白的相互作用，参与调控脊髓图式形成、蓝斑发育、神经干细胞分化、突触活性、少突胶质细胞分化等的分子机制，揭示了其可能的致病机制，圆满完成并拓展了预定研究计划。相关成果在主流学术刊物上发表研究论文6篇，应邀撰写综述一篇，培养博士研究生4名，应邀参加国际ZC4H2学术研讨会一次。