Bigl M, Apelt J, Luschekina E A, Lange-Dohna C, Rossner S, Schliebs R
Institute of Biochemistry, University of Leipzig, Liebigstrasse 16, D-04103 Leipzig, Germany.
Neurosci Lett. 2000 Oct 6;292(2):107-10. doi: 10.1016/s0304-3940(00)01452-x.
On the basis of the recent cloning of the beta-secretase, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), (Science, 286 (1999) 735), digoxigenin-labelled riboprobes were generated to localize the cellular expression pattern of BACE mRNA in brain sections of transgenic Tg2576 mice, overexpressing the Swedish mutation of the APP695 isoform. Non-radioactive in situ hybridization in combination with immunohistochemistry to identify the cell types and beta-amyloid deposits revealed strong BACE mRNA hybridization signals in neurons of the cerebral cortex, hippocampal formation, thalamus and cholinergic basal forebrain nuclei, while astrocytes did not display any labeling. Neurons surrounding beta-amyloid deposits did not demonstrate altered expression level of BACE mRNA as compared to neurons in cortical areas that are free of beta-amyloid deposits, and the regional expression pattern of BACE mRNA did not correlate with the distribution of beta-amyloid deposits. These data suggest that high level of expression of BACE mRNA is not necessarily related to enhanced deposition of beta-amyloid plaques. To elucidate those factors that contribute to beta-amyloid plaque deposition in a particular region, the transgenic Tg2576 mouse may represent an appropriate tool.
基于最近对β-分泌酶（β位点淀粉样前体蛋白（APP）裂解酶（BACE））的克隆（《科学》，286卷（1999年）735页），制备了地高辛配体标记的核糖探针，以定位过表达APP695亚型瑞典突变的转基因Tg2576小鼠脑切片中BACE mRNA的细胞表达模式。结合免疫组织化学进行非放射性原位杂交以鉴定细胞类型和β淀粉样蛋白沉积物，结果显示在大脑皮层、海马结构、丘脑和胆碱能基底前脑核的神经元中有强烈的BACE mRNA杂交信号，而星形胶质细胞未显示任何标记。与无β淀粉样蛋白沉积物的皮质区域的神经元相比，β淀粉样蛋白沉积物周围的神经元未显示BACE mRNA表达水平的改变，且BACE mRNA的区域表达模式与β淀粉样蛋白沉积物的分布无关。这些数据表明，BACE mRNA的高水平表达不一定与β淀粉样斑块的沉积增加有关。为了阐明导致特定区域β淀粉样斑块沉积的因素，转基因Tg2576小鼠可能是一种合适的工具。
