Ramakrishna N, Saikumar P, Potempska A, Wisniewski H M, Miller D L
Department of Molecular Biology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island 10314.
Biochem Biophys Res Commun. 1991 Jan 31;174(2):983-9. doi: 10.1016/0006-291x(91)91515-e.
The amyloid beta-peptide is a major constituent of amyloid deposited in the brains of patients with Alzheimer's disease and is derived from a larger precursor protein/s (APP-695, 751, 770). A human cDNA encoding full-length APP-751 was inserted into the genome of Autographa californica nuclear polyhedrosis virus under transcriptional regulation of the viral polyhedrin gene promoter. The recombinant virus was used to infect insect cells, which resulted in the abundant expression of APP-751. Analysis of infected cell proteins indicate that APP-751 is localized in the membrane fraction; however, a significant amount of the protein was cleaved and released into the medium. The NH2-terminal sequence of recombinant APP-751 from the membrane fraction was identical to that of mammalian APP. Immunoblot analysis suggests that the secreted form results from cleavage within the beta-peptide.
淀粉样β肽是沉积在阿尔茨海默病患者大脑中的淀粉样蛋白的主要成分，它来源于一种或多种更大的前体蛋白（APP-695、751、770）。将编码全长APP-751的人类cDNA在病毒多角体蛋白基因启动子的转录调控下插入苜蓿银纹夜蛾核型多角体病毒的基因组中。重组病毒用于感染昆虫细胞，从而导致APP-751的大量表达。对感染细胞蛋白的分析表明，APP-751定位于膜部分；然而，大量的该蛋白被切割并释放到培养基中。来自膜部分的重组APP-751的NH2末端序列与哺乳动物APP的序列相同。免疫印迹分析表明，分泌形式是由β肽内的切割产生的。
