mRNA二级结构对重组人白血病抑制因子(rhLIF)在大肠杆菌中表达的影响

The Effect of mRNA Secondary Structure on rhLIF Expression

真细菌中翻译起始效率通常是由翻译起始位点两侧的ｍ ＲＮＡ 区域二级结构的稳定性决定的．这种稳定性与该区域ＲＮＡ 二级结构的发生自由能（ΔＧ０ ）相对应．重组人白血病抑制因子（ｒｈＬＩＦ）为具有诱导白血病细胞分化、调节骨组织的生长代谢、维持胚胎干细胞的基本特征、促进神经元的分化等广泛生物学活性的细胞因子．为了获得高表达的ＬＩＦ蛋白，通过翻译起始区的位点专一突变，把具有优选密码子和能量优势的ｌｉｆ 片段克隆入ｐＪＬＡ５０３ 载体，然后转化至大肠杆菌中表达，得到表达量提高１０

The efficiency of translational initiation in eubacteria is generally determined by local properties of the mRNA regions flanking the translational start site and the stability of local secondary structure. The stability is dictated by the free energy (Δ G °) of the local RNA translational initiation region. Human leukemia inhibitory factor (LIF) is a pleiotropic cytokine with the ability of influencing the differentiation and metabolism of many body elements,such as blood cells,embryonal cells,neurons,adipose tissues,and bone. By site directed mutagenesis method,energy biased lif fragment was cloned into high effective expression vector pJLA503. After transformed with recombinant plasmids,the host bacteria expresses rhLIF by temperature induction,and obtained a predicted increase in expression.