Objective:To prepare GST-Orai2 fusion protein and to prepare polyclonal antibody against Orai2 by immunizing rabbits.To further investigate the function of Orai2,a transmembrane protein,this antibody was used to identify the Orai2 conditional gene knockout mice.Methods:ORF of Orai2 was amplified by PCR and subcloned into pGEX-6p-1 vector.After transforming BL21 (DE3) competent cells,we succeeded in inducing the expression of GST-Orai2 fusion protein using IPTG.Then the GST-Orai2 protein was purified by immobilized Glutathione affinity chromatography and identified by SDS-PAGE.A New England rabbit was immunized with the prepared fusion protein in Freund's adjuvant to prepare specific antibody.Finally,the prepared antibody was identified by Western blot by checking its titer and specificity.Furthermore,we took use of the prepared Orai2 antibody to identify Orai2 conditional gene knockout mice,with comparing to the wildtype ones in the same cage.Results:The purity of purified GST-Orai2 reached to 90% and the concentration was 0.35 mg/ml by BCA kit.We could detect Orai2 protein even in dilution of 1:10,000.Also,the prepared polyclonal antibody agianst Orai2 could detect both overexpressed and endogenous Orai2 protein in mouse-brain,without crossing reaction with Orai1.As well,we found that the Orai2 protein expression was of obvious reduction in Orai2 conditional gene knockout mice,compared with the wildtype ones in the same cage.Conclusion:We successfully obtain the purified GST-Orai2 fusion protein and prepare specific and highly sensitive polyclonal antibody against Orai2.The antibody can be used to detect overexpressed and endogenous Orai2 protein inmouse-brain specifically,and to identify Orai2 conditional gene knockout mice,without any crossing reaction with Orai1.Our work contributes a lot to the future investigation of functions of Orai2.%目的:原核表达跨膜蛋白Orai2的GST融合蛋白,获得高敏感性、高特异性的兔抗Orai2多克隆抗体,用于Orai2条件性基因敲除小鼠鉴定及Orai2蛋白功能研究.方法:PCR扩增Orai2 CDS编码序列,亚克隆到编码GST的pGEX-6p-1原核表达载体上,将编码Orai2的pGEX-6p-1-Orai2重组质粒化学转化BL21(DE3)感受态细胞,IPTG诱导GST-Orai2融合蛋白表达,经固化的谷胱苷肽琼脂糖珠亲和纯化,透析浓缩,获得用于免疫的高纯度GST-Orai2融合蛋白.SDS-PAGE鉴定后,将纯化的融合蛋白辅以弗氏佐剂,按常规方法免疫新西兰大白兔以制备多克隆抗体.Western blot检测抗体效价和特异性,并进行Orai2条件性基因敲除小鼠和同窝野生型小鼠脑组织鉴定.结果:经亲和纯化后的GST-Orai2融合蛋白纯度较高,BCA蛋白定量检测试剂盒测定蛋白浓度约0.35 mg/ml.抗Orai2多抗抗体效价达1:10 000.能特异性识别转染真核细胞获得的过表达Orai2,以及小鼠脑组织内源性的Orai2蛋白,而不与Orai1发生交叉反应.同时,用自制的Orai2多克隆抗体检测发现,与同窝野生型小鼠相比,Orai2条件性基因敲除小鼠脑组织中Orai2蛋白表达明显降低.结论:成功表达并纯化了GST-Orai2融合蛋白,获得了高敏感度、特异性的抗Orai2蛋白的多克隆抗体,该抗Orai2多抗能特异性识别过表达的和小鼠脑组织内源性Orai2蛋白,能对Orai2条件性基因敲除小鼠和同窝野生型小鼠脑组织进行鉴定,且与Orai1没有交叉反应,为进一步研究Orai2功能奠定了基础.
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