Expression, purification Orai2 protein and preparation, application it's polyclonal antibody / 中国免疫学杂志

ABSTRACT

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 110,000.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.