中文摘要：

研究转运膜蛋白21（TMP21）在小鼠胚胎成纤维细咆中超表达对PS-1及NCT蛋白表达量的影响．脂质体介导TMP21cDNA转染敲除淀粉样前体蛋白表达基因的小鼠胚胎成纤维细胞系（MEF（KO）），以梯度浓度G418筛选TMP21表达量最高的细胞．处理超表达组（T）和对照组（C）细胞。并收集纯化过程中含γ分泌酶复合物的样本，用Western blotting检测γ分泌酶复合物重要组分Nieastrin（NCT）、Presenilin-1（PS-1）以及TMP21的蛋白表达量．结果表明，样本T1、T2及IPT2所含TMP21的蛋白表达量较相应对照组样本C1、C2和IPC2分别上升11．5％（P=0．08）、28．1％（P〈0．01）及69．1％（P〈0．001），提示经TMP21cDNA转染后MEF（KO）细胞中TMP21蛋白表达明显提高，而转染组和对照组中，构成γ分泌酶复合物的重要组分NCT与PS-1蛋白表达量无明显变化．这表明在TMP21蛋白高表达状态下．不会影响MEF（KO）细胞中γ分泌酶复合物的重要组分NCT与PS-1蛋白表达量．

英文摘要：

Objective Previous studies have revealed that γ-secretase is involved in the pathogenesis of Alzheimer＇s disease. The impacts of the transmembrane protein 21 （TMP21） protein levels ofγ-secretase components were investigated in APP knockout mouse embryonic fibroblasts（MEF（KO））. Methods MEF（KO） was transfectted with TMP21 cDNA to induce protein expression. During the purification of γ-secretase, samples comprising γ- secretase complex were collected in transfection（T） or control（C） group at three phases. The samples were respectively marked as follbw. T1 and C1 which included the whole cell membrane proteins;T2 and C2 which were the lysates by CHAPSO; IPT2 and IPC2 which were prepared after co-immunoprecipitation by presenilin-1 antibody. The protein levels of TMP21 and γ-secretase components,presenilin-1（PS-1） and Nicastrin（NCT）,were detected by Western blotting. Results Compared with C1, C2 and IPC2, the protein levels of TMP21 in T1, T2 and IPT2 were, respectively,increased by 11.5%（P=0.08）,28. 1% （P〈0.01） and 69. 1% （P〈0. 001）; meanwhile,no change in protein levels of NCT and PS-1 was observed. Conclusions The protein levels of the γ-secretase components presenilin-1 （PS-1） and Nicastrin （NCT） were not impacted when the TMP21 was overexpressed.