Generation of transgenic mice to investigate the expression patterns, protein interactions and physiological functions of P2X4, P2X6 and P2X7 receptors

P2 X受体（P2 XRs）是ATP激活的Ca 2+可渗透的阳离子通道，已被证明影响多种细胞功能。通常在给定的组织或细胞类型中表达七种已知的P2 X亚基（P2 X1-P2 X7）中的一种以上。天然组织中P2 XR的功能表征受到激动剂的快速催化、不同P2 XR亚型和代谢型P2 Y受体的同时活化以及缺乏亚型特异性配体的阻碍。因此，P2 XR的体内功能在很大程度上是未知的。小鼠单个P2 X基因的缺失揭示了P2 XRs参与骨生成、白细胞介素产生、排尿、疼痛传递和生殖等多种生理过程。尽管P2 XR在脑中广泛表达，但迄今为止在可用的敲除动物中尚未鉴定出对运动功能或行为的影响。然而，电生理学研究表明P2 XRs在突触传递的调节和神经病理性疼痛的发展中起重要作用。在本项目中，我们拟通过构建在内源性启动子下过表达表位标记和显性负性P2 X亚基的转基因小鼠，研究P2 X4、P2 X6和P2 X7亚基在哺乳动物中枢神经系统神经胶质细胞和神经元中的表达模式、功能和蛋白质相互作用。

P2X receptors (P2XRs) are ATP-activated Ca2+-permeable cation channels that have been shown to influence a variety of cell functions. Usually more than one of the seven known P2X subunits (P2X1-P2X7) are expressed in a given tissue or cell type. The functional characterization of P2XRs in native tissues has been hampered by the rapid catabolism of the agonist, the simultaneous activation of different P2XR subtypes and metabotropic P2Y receptors as well as the lack of subtype-specific ligands. Therefore, the in vivo functions of P2XRs are largely unknown. Deletion of single P2X genes in mice revealed the involvement of P2XRs in such diverse physiological processes as osteogenesis, interleukine production, micturition, pain transmission and reproduction. Despite the wide-spread expression of P2XRs in brain, no effects on motor function or behavior have been identified so far in the available knockout animals. However, electrophysiological studies indicate an important role of P2XRs in the modulation of synaptic transmission and the development of neuropathic pain. In this project, we propose to generate transgenic mice that over-express epitope-tagged and dominant-negative P2X subunits under their endogenous promoters to investigate the expression patterns, functions and protein interactions of P2X4, P2X6 and P2X7 subunits in glia cells and neurons of the mammalian central nervous system.