Doppel-induced cytotoxicity in human neuronal SH-SY5Y cells is antagonized by the prion protein  

作　　者：Ping Li Chenfang Dong Yanjun Lei Bing Shan Xinli Xiao Huiying Jiang Xin Wang Chen Gao Qi Shi Kun Xu Chan Tian Jun Han Xiaoping Dong 

机构地区：[1]State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China [2]School of Medicine, Xi'an Jiao-Tong University, Xi'an 710061, China

出　　处：《Acta Biochimica et Biophysica Sinica》2009年第1期42-53,共12页生物化学与生物物理学报（英文版）

基　　金：Acknowledgements We thank Mr Baoyun Zhang and Tongxin Zhao for their excellent technical supports. We are indebted to Dr Jian-Mei Gao for her helpful discussion. This work is supported by the National Science and Technology Task Force Project （2006BAD06A13-2）, National Basic Research Program of China （973 Program） （2007CB310505）, and Chinese National Natural Science Foundation Grants 30771914, 30571672 and 30500018.

摘　　要：Doppel （Dpl） is a prion （PrP）-like protein due to the structural and biochemical similarities; however, the natural functions of Dpl and PrP remain unclear. In this study, a 531-bp human PRND gene sequence encoding Dpl protein was amplified from human peripheral blood leucocytes. Furl-length and various truncated human Dpl and PrP proteins were expressed and purified from Escherichia coil Supplement of the full-length Dpl onto human neuroblastoma cell SH-SY5Y induced remarkable cytotoxicity, and the region responsible for its cytotoxicity was mapped at the middle segment of Dpl [amino acids （aa） 81-122]. Interestingly, DpMnduced cytotoxicity was antagonized by the presence of full- length wild-type PrP. Analysis on fragments of PrP mutants showed that the N-terminal fragment （aa 23- 90） of PrP was responsible for the protective activity. A truncated PrP （PrPA32-121） with similar secondary structure as Dpl induced DpMike cytotoxicity on SH- SY5Y cells. Furthermore, binding of copper ion could enhance the antagonizing effect of PrP on Dpi-induced cytotoxicity. Apoptosis assays revealed that cytotoxicity induced by Dpl occurred through an apoptotic mechanism. These results suggested that the function of Dpl is antagonistic to PrP rather than synergistic.Doppel （Dpl） is a prion （PrP）-like protein due to the structural and biochemical similarities; however, the natural functions of Dpl and PrP remain unclear. In this study, a 531-bp human PRND gene sequence encoding Dpl protein was amplified from human peripheral blood leucocytes. Furl-length and various truncated human Dpl and PrP proteins were expressed and purified from Escherichia coil Supplement of the full-length Dpl onto human neuroblastoma cell SH-SY5Y induced remarkable cytotoxicity, and the region responsible for its cytotoxicity was mapped at the middle segment of Dpl [amino acids （aa） 81-122]. Interestingly, DpMnduced cytotoxicity was antagonized by the presence of full- length wild-type PrP. Analysis on fragments of PrP mutants showed that the N-terminal fragment （aa 23- 90） of PrP was responsible for the protective activity. A truncated PrP （PrPA32-121） with similar secondary structure as Dpl induced DpMike cytotoxicity on SH- SY5Y cells. Furthermore, binding of copper ion could enhance the antagonizing effect of PrP on Dpi-induced cytotoxicity. Apoptosis assays revealed that cytotoxicity induced by Dpl occurred through an apoptotic mechanism. These results suggested that the function of Dpl is antagonistic to PrP rather than synergistic.

关 键 词：DOPPEL PRION CYTOTOXICITY APOPTOSIS 

分 类 号：Q51[生物学—生物化学]