Ali S M, Siedlak S L, Gonzalez-DeWhitt P A, Altman R A, Glendening J M, Lowery D E, Savage M J, Polites H G, Perry G, Greenberg B D
Upjohn Company, Kalamazoo, MI 49001, USA.
Neurobiol Aging. 1996 Mar-Apr;17(2):223-34. doi: 10.1016/0197-4580(95)02065-9.
In an attempt to generate transgenic mice modeling Alzheimer-type amyloidogenesis, the COOH-terminal 103 residue human APP segment was expressed in brain regions known to be vulnerable in AD. Transfected cells overexpressing this transgene were previously shown to develop intracytoplasmic inclusions that were immunoreactive with antibodies to the APP COOH-terminus. Transgenic C57B6/SJL mice produced transgene-coded mRNA in their brains at levels up to sixfold above endogenous APP, most abundantly within cortical and hippocampal pyramidal neurons. Immunocytochemistry with anti-A beta antibodies revealed occasional structures that resembled diffuse amyloid, but which could not be detected on serial sections. Immunolabeling with antibodies to APP regions NH2-terminal to the transgene-coded domain revealed elevated immunoreactivity within perikarya and neurites in regions expressing the highest transgene and endogenous APP mRNA levels, similar to observations previously reported within vulnerable neurons in AD brain. However, subsequent breeding revealed that this phenotype segregated with the B6/SJL background rather than the transgene, thus emphasizing the importance of genetic background to observations of putative AD-type pathology in transgenic animals.
为了构建模拟阿尔茨海默病淀粉样变的转基因小鼠，将人APP羧基末端103个氨基酸残基片段在已知对AD易感的脑区进行表达。先前已显示，过表达该转基因的转染细胞会形成与APP羧基末端抗体发生免疫反应的胞浆内包涵体。转基因C57B6/SJL小鼠脑内产生的转基因编码mRNA水平比内源性APP高6倍，在皮质和海马锥体细胞中最为丰富。用抗Aβ抗体进行免疫细胞化学检测发现偶尔有类似弥漫性淀粉样物质的结构，但在连续切片上无法检测到。用转基因编码结构域氨基末端的APP区域抗体进行免疫标记显示，在转基因和内源性APP mRNA表达水平最高的区域，核周体和神经突内的免疫反应性升高，这与先前在AD脑易感神经元中的观察结果相似。然而，随后的繁殖实验表明，这种表型与B6/SJL背景而非转基因相关，从而强调了遗传背景对转基因动物中假定的AD型病理学观察的重要性。
