Analyses of the function of Prrt3, an orphan family C metabotropic recptor

Prrt3是C家族的孤儿代谢性受体，其N端胞外区较大，有7个跨膜区。为了探讨Prrt3的功能，我们制作了基因敲除(KO)小鼠。由于KO同系小鼠的存活率很低，我们使用KO异种小鼠进行了行为测试电池分析。KO异种小鼠在空间记忆和恐惧条件性记忆的长时记忆中存在异常。我们还用特异性抗体分析了Prrt3蛋白在脑内的表达模式，并观察到丘脑、小脑皮质、海马区和黑质的特异性染色。通过比较Prrt3蛋白和mRNA在海马区的表达模式，发现Prrt3蛋白不定位于神经元胞体，而定位于神经元突起。我们还用截短型Prrt3的特异性抗体通过免疫印迹观察到存在缺失N端胞外区的Prrt3。

Prrt3 is an orphan family C metabotropic receptor with a large N-terminus extracellular domain and 7 transmembrane regions. To approach the function of Prrt3, we made a gene knock-out (KO) mice. As the survival rate of KO homo was very low, we performed behavioral test battery analyses using KO hetero mice. KO hetero mice abnormality in the long term retention of spatial memory and fear- conditioning memory. We also analyzed the expression pattern of Prrt3 protein in the brain by specific antibodies, and observed specific staining in thalamus, cerebellar cortex, hippocampus and substantia nigra. By comparing the protein and mRNA expression patterns in the hippocampus, it was shown Prrt3 protein is localized not in neuronal cell bodies but in neurites. We also observed by western blotting using specific antibodies that truncated form of Prrt3 lacking the N-terminus extracellular region exist.