鸡β_2微球蛋白基因克隆及其在大肠杆菌中的高效表达与纯化

Cloning,expression and purification of chicken β_2-microglobulin in Escherichia coli

β2微球蛋白(β2m)是组成主要组织相容性复合体(MHC)Ⅰ类分子复合体的轻链分子,对于MHCⅠ类分子在细胞表面稳定表达和有效递呈抗原肽必不可少。本试验从来航鸡全血细胞中克隆了鸡β2m(Chβ2m)全基因,利用软件预测了其信号肽序列,并构建了表达成熟Chβ2m的重组载体,在大肠杆菌表达系统中以包涵体形式高效表达。将所得包涵体溶于8 mol/L脲,并在变性条件下对包涵体中的重组Chβ2m进行纯化,获得了高纯度的Chβ2m,为制备MHCⅠ四聚体及探索禽类MHCⅠ类分子结构与功能的关系提供了条件。

In this experiment, the chicken β2m gene was cloned by reverse transcription polymerase chain reaction （RT-PCR） from the Leghorn whole blood. The software SignalP 3.0 was used to predict the signal peptide of chicken β2m gene. The chicken β2m gene （absent signal peptide sequence） was then subcloned into an expression vector pET-28a （ ＋ ） and expressed efficiently in prokaryotic expression system. The target protein was found in the inclusion body fraction, so the purification of the recombinant chicken β2m was performed under denaturing conditions at room temperature. The high quality chicken β2m laid a good foundation for preparation of MHC Ⅰ tetramer and study on the relationship between the configuration of chicken MHC Ⅰ and its functions.