Lah J J, Heilman C J, Nash N R, Rees H D, Yi H, Counts S E, Levey A I
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
J Neurosci. 1997 Mar 15;17(6):1971-80. doi: 10.1523/JNEUROSCI.17-06-01971.1997.
Several genes have been implicated in the pathogenesis of early-onset familial Alzheimer's disease. A majority of the autosomal dominant cases are linked to recently identified mutations in the presenilin-1 gene on chromosome 14. The native presenilin-1 protein in primates has not been well characterized, and its precise localization is unknown. We have studied the native presenilin-1 protein in monkey brain and peripheral tissues by using a monoclonal antibody specific for the N-terminal domain of human presenilin-1. Western blots detect polypeptide species of approximately 49 and approximately 32 kDa from COS-7 and PC12 cells transfected with full-length human presenilin-1 cDNA and from in vitro translations of the normal human presenilin-1 mRNA. A 32 kDa polypeptide is detected in monkey peripheral tissues, with the highest expression in testis and lung. In all brain regions the 32 kDa band is the predominant form of presenilin-1, and it is found in particulate subfractions. Light microscopic immunocytochemistry reveals presenilin-1 staining in all brain regions, with the strongest labeling in neurons and neuropil. In addition, weaker immunoreactivity is also present in glia and blood vessels. Neuronal staining shows significant variability, with particularly intense labeling of certain cell types, including large neocortical and hippocampal pyramidal neurons, magnocellular basal forebrain neurons, brainstem motoneurons, and some populations of interneurons. By electron microscopic immunocytochemistry, highly selective presenilin-1 staining is seen on the cytoplasmic surfaces of membranous organelles, which suggest localization to the endoplasmic reticulum-Golgi intermediate compartment, a subdomain of the endoplasmic reticulum, and some coated transport vesicles.
几个基因与早发性家族性阿尔茨海默病的发病机制有关。大多数常染色体显性病例与最近在14号染色体上早老素-1基因中发现的突变有关。灵长类动物体内的天然早老素-1蛋白尚未得到很好的表征，其确切定位也不清楚。我们使用一种针对人早老素-1 N端结构域的单克隆抗体，研究了猴脑和外周组织中的天然早老素-1蛋白。蛋白质免疫印迹法检测到，在用全长人早老素-1 cDNA转染的COS-7和PC12细胞以及正常人早老素-1 mRNA的体外翻译产物中，存在大约49 kDa和大约32 kDa的多肽。在猴外周组织中检测到一种32 kDa的多肽，在睾丸和肺中表达最高。在所有脑区，32 kDa条带是早老素-1的主要形式，并且存在于微粒亚组分中。光学显微镜免疫细胞化学显示，早老素-1在所有脑区均有染色，在神经元和神经纤维中标记最强。此外，在胶质细胞和血管中也存在较弱的免疫反应性。神经元染色显示出显著的变异性，某些细胞类型的标记特别强烈，包括大脑新皮质和海马的大锥体细胞、基底前脑大细胞神经元、脑干运动神经元以及一些中间神经元群体。通过电子显微镜免疫细胞化学观察到，在膜性细胞器的胞质表面有高度选择性的早老素-1染色，这表明其定位于内质网-高尔基体中间区室，即内质网的一个亚结构域，以及一些有被转运小泡。
