人LINGO-1aa76-319蛋白的原核表达及多克隆抗体制备

目的 表达和纯化带多聚组氨酸(6×His)标签的人LINGO-1胞外段(hLINGO-1_(aa76-319))融合蛋白,并制备兔源性抗hLINGO-1_(aa76-319)的多克隆抗体(pAb).方法 利用PCR从pCMV-SPORT6获得hLINGO-1_(aa76-319)编码序列,将其亚克隆至原核表达载体pET30a(+),构建重组表达质粒pET30a(+)-hLINGO-1_(aa76-319);将阳性重组质粒转化大肠杆菌,IPTG诱导表达6×His-hLINGO-1_(aa76-319)融合蛋白,经Ni-NTA螯合树脂纯化,纯化蛋白免疫新两兰大白兔制备多克隆抗血清,Protein A Sepharose柱纯化获得多抗,ELISA法检测抗体效价,Western blot法检测抗体特异性.结果 成功构建了pET30a(+)-hLINGO-1_(aa76-319)原核表达载体,原核蛋白hLINGO-1_(aa76-319)以包涵体形式在大肠杆菌高水平表达,通过复性与亲和层析获得纯度在90% 以上的hLINGO-1_(aa76-319)蛋白,蛋白浓度为4600 mg/L,制备的抗hLINGO-1_(aa76-319)多抗效价高达1:1.6×106,Western blotting鉴定其具有良好的特异性.结论 获得高纯度hLINGO-1_(aa76-319)蛋白并成功制备特异性pAb,为进一步研究LINGO-1的生物学功能提供实验基础.

Abstract：

Objective To express and purify the fusion protein of extracellular domain of human Ig domain-containing, neurite outgrowth inhibitor (Nogo) receptor-interacting protein-1 (LINGO-1_(aa76-319)) in prokaryotic cells and prepare the rabbit anti-LINGO-1 polyclonal antibody (pAb). Methods The 732 bp DNA sequence of hLINGO-1_(aa76-319), was obtained from pCMV-SPORT6 by PCR and inserted into pET30a (+) plasmid to construct the prokaryotic expression plasmid pET30a(+) -hLINGO-1_(aa76-319) which was subsequently transformed into E.coli. The target fusion protein was expressed with IPTG induction and purified by Ni~(2+)-NTA affinity chromatography column. The antiserum against hLINGO-1_(aa76-319) was obtained from the rabbits immunized with hLINGO-1 _(aa76-319), and the titer of the pAb was determined using enzyme linked immunosorbent assay (ELISA) and its specificity identified using Western blotting. Results The prokaryotic expression plasmid pET30a (+)-hLINGO-1_(aa76-319) was constructed successfully. Efficient expression of the target fusion protein was achieved with IPTG induction at the optimal concentration of 0.4 mmol/L and culture temperature at 37 ℃ for 2.5 h. The hLINGO-1_(aa76-319) fusion protein was effectively expressed in E.coli as inclusion bodies, and the soluble protein was obtained through denaturation and refolding procedures, and the purified fusion protein showed a purity above 90%. The titer of the anti-hLINGO-1_(aa76-319) pAb obtained by immunizing the rabbits with the purified protein reached l:1.6×10~6, and Western blotting confirmed its good specificity. Conclusion The fusion protein hLINGO-1_(aa76-319) with high purity has been obtained and the anti-hLINGO-1_(aa76-319) pAb obtained shows a high titer and good specificity, which provide important experimental basis for further functional investigation of LINGO-1.

Prokaryotic expression,purification of human LINGO-1_(aa76-319) and preparation of its polyclonal antibody

Objective To express and purify the fusion protein of extracellular domain of human Ig domain-containing, neurite outgrowth inhibitor (Nogo) receptor-interacting protein-1 (LINGO-1_(aa76-319)) in prokaryotic cells and prepare the rabbit anti-LINGO-1 polyclonal antibody (pAb). Methods The 732 bp DNA sequence of hLINGO-1_(aa76-319), was obtained from pCMV-SPORT6 by PCR and inserted into pET30a (+) plasmid to construct the prokaryotic expression plasmid pET30a(+) -hLINGO-1_(aa76-319) which was subsequently transformed into E.coli. The target fusion protein was expressed with IPTG induction and purified by Ni~(2+)-NTA affinity chromatography column. The antiserum against hLINGO-1_(aa76-319) was obtained from the rabbits immunized with hLINGO-1 _(aa76-319), and the titer of the pAb was determined using enzyme linked immunosorbent assay (ELISA) and its specificity identified using Western blotting. Results The prokaryotic expression plasmid pET30a (+)-hLINGO-1_(aa76-319) was constructed successfully. Efficient expression of the target fusion protein was achieved with IPTG induction at the optimal concentration of 0.4 mmol/L and culture temperature at 37 ℃ for 2.5 h. The hLINGO-1_(aa76-319) fusion protein was effectively expressed in E.coli as inclusion bodies, and the soluble protein was obtained through denaturation and refolding procedures, and the purified fusion protein showed a purity above 90%. The titer of the anti-hLINGO-1_(aa76-319) pAb obtained by immunizing the rabbits with the purified protein reached l:1.6×10~6, and Western blotting confirmed its good specificity. Conclusion The fusion protein hLINGO-1_(aa76-319) with high purity has been obtained and the anti-hLINGO-1_(aa76-319) pAb obtained shows a high titer and good specificity, which provide important experimental basis for further functional investigation of LINGO-1.