单基因变异导致的多聚谷氨酰胺（PolyQs）疾病发病机制的研究是国际上神经病学的研究热点。近期研究发现内质网应激和未折叠蛋白反应是PolyQs病早期事件,本课题基于申请人前期研究发现转录因子CCAAT增强子结合蛋白同源蛋白（CHOP）的转录及蛋白水平在PolyQs诱导的内质网应激和未折叠蛋白反应中明显升高，并在细胞核内大量聚集的结果，通过亨廷顿舞蹈病（HD）和脊髓小脑共济失调3型（SCA3）的细胞模型,运用荧光素酶报告基因检测、免疫共沉淀、染色质免疫沉淀、免疫荧光、lightCycler PCR、亚细胞成分分析来研究变异PolyQs蛋白对CHOP转录水平增高的上游调控机制，PolyQs对CHOP转录活性的影响及其可能机制，以及PolyQs蛋白对CHOP诱导的凋亡通路作用的影响。应用外源性转染CHOP siRNA干预方法结合电镜技术，研究下调CHOP水平可能减轻变异POlyQs蛋白毒性作用。

The study of the pathogenesis of polyglutamine (polyQs) diseases caused by Single-gene mutation is an international research focus on neurology. Recent studies found the endoplasmic reticulum stress (ER stress) and the unfolded protein response (UPR) are early events in PolyQs diseases. Based on our findings that transcriptional and protein levels of CCAAT enhancing binding protein homologous protein (CHOP),a transcriptional facor, are elevated in PolyQs induced ER stress and UPR and accumulated dramatically in the nuclear, this project aims to study possible upstream regulatory mechanism underlying the elevated CHOP mRNA level in response to PolyQs proteins, the effect of PolyQs on the transcriptional activity of CHOP and the possible underlying mechanisms as well as the effects of polyQs protein on CHOP-induced apoptotic pathway in Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) cell models by using gene transfection, luciferase reporter gene detection, co-immunoprecipitation, chromatin immunoprecipitation, immunofluorescence, lightCycler PCR and sub-cellular components analysis.The project also aims to study the possible rescue effects of down regulation of CHOP by using CHOP siRNA on cytotoxicity of polyQ proteins.