酵母双杂交技术筛选人白细胞cDNA文库中HCV NS4A结合蛋白及CAML基因的克隆

目的应用酵母双杂交技术筛选人白细胞中与丙型肝炎病毒非结构蛋白4A(HCV NS4A)相互作用的蛋白。方法连接有HCV NS4A酵母表达的载体pGBKT7-NS4A,转化入单倍体酵母细胞AH109,与转化了人白细胞cDNA文库质粒的单倍体酵母细胞Y187进行配合,在营养缺陷型培养基和X-a-半乳糖(X-a-Gal)上进行双重筛选阳性菌落,增菌后提取质粒,转化入大肠埃希细菌(DH5α),提取质粒并测序,进行生物信息学分析。对克隆重复率较高的蛋白编码基因进行克隆和回交验证。结果筛选出在四缺(SD/-Trp-Leu-Ade-His)培养基和在铺有X-a-gal的四缺培养基上均能生长并变成蓝色的真阳性菌落45个,其中钙离子信号调节亲环素配体(CAML)29个。对CAML基因成功克隆,回交验证了HCV NS4A与CAML的相互作用。结论成功筛选出7种在人白细胞cDNA文库中与HCV NS4A特异性相互作用的蛋白,为进一步探讨HCV的致病机制提供了新的线索。

Screebning and identification of proteins interacting with HCV NS4A via yeast double hybridization in leukocytes and gene cloning of the interacting protein

OBJECTIVE: To screen proteins interacting with HCV NS4A protein in leukocytes by yeast-double hybridization. METHODS: The bait plasmid pGBKT7-NS4A was transformed into yeast AH109 was transformed, and the expressing of the fusion protein was identified by SDS-page. The transformed yeast was mated with yeast Y187 containing leukocytes cDNA library plasmid in 2xYPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal for selecting two times and screening. After extracting and sequencing of plasmid from blue colonies, analysis was conducted by bioinformatics. And, the gene encoding the interesting protein was cloned, and back-cross was performed. RESULTS: Forty-five colonies were sequenced, among them, 29 colonies were human calcium modulating cyclophilin ligand (CAML). The gene encoding CAML was cloned, and the interaction between NS4A and CAML was ensured. CONCLUSION: Seven kinds of proteins interacting with NS4A in leukocytes were successfully screened and the results brought some new clues for studying the pathogenesis of HCV.