人重组钙依赖性磷脂结合蛋白Ⅴ在大肠杆菌中的高效表达、纯化及细胞凋亡检测

The expression and purificiation of human Annexin Ⅴ overexpressed in E. coli and the detection of apoptosis

目的 :为细胞凋亡研究提供快速可靠的实验方法。方法 :利用RT PCR技术从人外周血单核细胞系U937cDNA文库中扩增出编码钙依赖性磷脂结合蛋白Ⅴ (AnnexinⅤ )cDNA ,并克隆到大肠杆菌表达载体中 ,在大肠杆菌中表达含凝血酶识别序列的MS2AnnexinⅤ融合蛋白。表达产物经凝血酶消化 ,可除去MS2细菌蛋白 ,再经离子交换层析纯化 ,可得成熟的AnnexinⅤ纯品 ,FITC标记后的AnnexinⅤ可用于细胞凋亡的检测。结果 :在大肠杆菌表达的人重组AnnexinⅤ占菌体蛋白的 5 6 % ,经纯化获得 99%纯度的非融合型AnnexinⅤ ,FITC标记的An nexinⅤ能有效地检测凋亡细胞。结论 :成功地建立了批量获取AnnexinⅤ的技术路线 。

SUMMARY Objective: in order to provide rapid and reliable method. Methods: Encoded Annexin Ⅴ cDNA was amplifyed from U937 cDNA libary by PCR and then subcloned into E coli expression vector. MS2 Annexin Ⅴ fusion protein could be overexpressed in E coli . The MS2 bacteria protein could be removed by thrombin digestion.The mature Annexin Ⅴ was obtained by ion exchange chromatography and the FITC labled Annexin Ⅴ could be used in the detection of apoptosis. Results:Up to 37% of the total bacterial proteins was rhAnnexin Ⅴ as showed by SDS PAGE. The purification of Annexin Ⅴ is over 99%. The FITC labled Annexin Ⅴ could efficiently detect apoptosis. Conclusion: We successfully established the technique procedure of obtaining a large quantity of Annexin Ⅴ and provided the basic routine for popularizing the detection of apoptosis' with high effciency.