外显子组测序在一常染色体隐性小脑共济失调家系发现一新致病基因UX-E1，为UX类泛素化通路激活酶。UX从人到植物均保守，但其生物学功能有待研究。我们发现UX-E1及UX和UX-E2敲低果蝇均表现出翅膀、爬行、飞行、寿命及神经肌肉接头等方面神经变性，可模拟患者表型。过表达野生型UX-E1显著拯救神经变性，而突变型无法有效拯救。目前只在HEK293与MIN6胰岛细胞中鉴定出两个UX靶基因，且小鼠脑组织中存在特异的UX结合蛋白条带。我们拟利用SILAC这一理想的翻译后修饰定量蛋白质组平台，在UX基因前加6×His标签小鼠中鉴定神经系统中高可信UX靶基因；利用果蝇这一大规模筛选优秀模型，对350种缺陷型果蝇、3200种化合物进行筛选，找到影响神经退行表型的modifiers。基于以上，我们将体内外证明UX通路及靶基因发挥的生物学功能，阐明UX-E1突变导致小脑共济失调的致病机制并发现特异治疗靶点。

The mutations in a novel gene UX-E1, an ubiquitin-like modifier activating enzyme, were determined through exome-sequencing in an autosomal recessive cerebellar ataxia cohort. The understanding of biological function of UX cascade remains largely elusive, although UX is present in nearly all eukaryotic organisms with the exception of fungi. We observed RNAi knockdown of UX-E1, UX, or UX-E2 exhibits abnormal wing positioning, climbing and flight defects, short life-span and abnormal NMJ morphology, which perfectly mimics the neurodegenerative phenotypes of the patients. Overexpression of human and drosophila UX-E1 effectively rescued the neurodegeneration, while mutant UX-E1 failed. To date, only two targets were reported in HEK293 and MIN6 pancreatic cell lines and distinct UX conjugates were found in the mouse brain tissue. We intend to identify UX targets in the central nervous system of knock-in mice with 6×His tag insertion upstream of UX gene through SILAC quantitative proteomics, an ideal platform for measuring dynamic post-translation modification changes. UX targets with high credibility will be validated by Co-IP, in vitro conjugation assay, subcellular fractionation, and in vivo fly targets rescue experiments. High-throughput screens of 350 deficiency Drosophila strains and 3200 chemical compounds have been performed, that may suggest proteins and molecular pathways that contribute to the disease process and thus provide novel targets for therapeutic interventions. Subsequent functional study will be conducted in the suitable cell lines and UX Drosophila model. Our study will point out UX targets and molecular pathways involved in the pathogenesis of the disease, elucidate the underlying molecular mechanism how mutations in UX-E1 caused the autosomal recessive cerebellar ataxia.