Blanchard V, Czech C, Bonici B, Clavel N, Gohin M, Dalet K, Revah F, Pradier L, Imperato A, Moussaoui S
Rhône-Poulenc Rorer, Centre de Recherche de Vitry-Alfortville, Vitry-sur-Seine, France.
Brain Res. 1997 May 30;758(1-2):209-17. doi: 10.1016/s0006-8993(97)00231-x.
Missense mutations of presenilin 1 (PS-1) and presenilin 2 (PS-2) genes cause the majority of early-onset familial forms of Alzheimer's disease (AD). We previously characterized the distribution of the PS-1 protein in the mouse brain by immunohistochemistry using an antibody directed against an epitope located in the large hydrophilic loop [Moussaoui, S., Czech, C., Pradier, L., Blanchard, V., Bonici, B., Gohin, M., Imperato, A. and Revah, F., Immunohistochemical analysis of presenilin 1 expression in the mouse brain, FEBS Lett., 383 (1996) 219-222]. Similarly, we now report the distribution pattern of PS-2 protein in the mouse brain. For these experiments we used a polyclonal antibody raised against a synthetic peptide corresponding to the amino-acid sequence 7-24 of the predicted human PS-2 protein. The specificity of the antibody was evidenced by its ability to recognize PS-2 protein in immunoprecipitation studies and by antigen-peptide competition. In the mouse brain, PS-2 protein was present in numerous cerebral structures, but its distribution in these structures did not correlate with their susceptibility to AD pathology. In all examined structures of the gray matter, PS-2 protein was concentrated in neuronal cell bodies but it was not detected in the glial cells of the white matter. The regional distribution pattern of PS-2 protein was almost identical to that of PS-1 protein. Moreover, PS-2 protein co-localized with PS-1 protein in a large number of neuronal cell bodies. In terms of subcellular localization, PS-2 immunostaining was present almost exclusively in neuronal cell bodies while PS-1 immunostaining was also present in dendrites. This could be explained by the different epitopes of the antibodies and the known proteolytic processing of both presenilins in vivo [Tanzi, R.E., Kovacs, D.M., Kim, T.-W., Moir, R.D., Guenette, S.Y. and Wasco, W., The presenilin genes and their role in early-onset familial Alzheimer's disease, Alzheimer's disease Rev., 1 (1996) 91-98]. Within neuronal cell bodies, the immunostaining of PS-2 protein, as well as that of PS-1 protein, had a reticular and granular appearance. This suggests in agreement with previous observations on PS-1 and PS-2 in COS and H4 cells [Kovacs, D.M., Fausett, H.J., Page, K.J., Kim, T.-W., Moir, R.D., Merriam, D.E., Hollister, R.D., Hallmark, O.G., Mancini, R., Felsenstein, K.M., Hyman, B.T., Tanzi, R.E., Wasco, W., Alzheimer-associated presenilins 1 and 2: neuronal expression in brain and localization to intracellular membranes in mammalian cells, Nature Med., 2 (1996) 224-229] that these proteins are situated in intracytoplasmic organelles, possibly the endoplasmic reticulum and the Golgi complex.
早老素1（PS-1）和早老素2（PS-2）基因的错义突变导致了大多数早发性家族性阿尔茨海默病（AD）。我们之前通过免疫组织化学方法，使用针对位于大亲水环中的一个表位的抗体，对小鼠脑中PS-1蛋白的分布进行了表征[穆萨维，S.，捷克，C.，普拉迪耶，L.，布兰查德，V.，博尼奇，B.，戈欣，M.，因佩拉托，A.和雷瓦，F.，小鼠脑中早老素1表达的免疫组织化学分析，《欧洲生物化学学会联合会快报》，383（1996）219 - 222]。同样，我们现在报告小鼠脑中PS-2蛋白的分布模式。对于这些实验，我们使用了一种针对对应于预测的人PS-2蛋白氨基酸序列7 - 24的合成肽产生的多克隆抗体。该抗体的特异性通过其在免疫沉淀研究中识别PS-2蛋白的能力以及抗原 - 肽竞争得以证明。在小鼠脑中，PS-2蛋白存在于众多脑结构中，但其在这些结构中的分布与它们对AD病理的易感性不相关。在所有检查的灰质结构中，PS-2蛋白集中在神经元细胞体中，但在白质的胶质细胞中未检测到。PS-2蛋白的区域分布模式与PS-1蛋白几乎相同。此外，PS-2蛋白在大量神经元细胞体中与PS-1蛋白共定位。就亚细胞定位而言，PS-2免疫染色几乎仅存在于神经元细胞体中，而PS-1免疫染色也存在于树突中。这可以通过抗体的不同表位以及体内两种早老素已知的蛋白水解加工来解释[坦齐，R.E.，科瓦奇，D.M.，金，T.-W.，莫伊尔，R.D.，格内特，S.Y.和瓦斯科，W.，早老素基因及其在早发性家族性阿尔茨海默病中的作用，《阿尔茨海默病评论》，1（1996）91 - 98]。在神经元细胞体内，PS-2蛋白以及PS-1蛋白的免疫染色呈现网状和颗粒状外观。这与之前在COS和H4细胞中对PS-1和PS-2的观察结果一致[科瓦奇，D.M.，福塞特，H.J.，佩奇，K.J.，金，T.-W.，莫伊尔，R.D.，梅里亚姆，D.E.，霍利斯特，R.D.，霍尔马克，O.G.，曼奇尼，R.，费尔森斯坦，K.M.，海曼，B.T.，坦齐，R.E.，瓦斯科，W.，与阿尔茨海默病相关的早老素1和2：在脑中的神经元表达以及在哺乳动物细胞中定位于细胞内膜，《自然医学》，2（1996）224 - 229]，表明这些蛋白位于胞质内细胞器中，可能是内质网和高尔基体复合体。
