鼠源ATP5B基因克隆及其原核和真核表达载体构建

Cloning of mouse ATP5B gene and construction of its prokaryotic and eukaryotic expression vectors

  • 摘要: 【目的】 克隆鼠源ATP5B基因,构建其原核和真核表达载体,为研究ATP5B蛋白功能及其在病毒感染过程中的作用机制提供基础。【方法】 克隆鼠源ATP5B基因编码区(CDS),运用ProtParam、ProtScale和SignalP-5.0等对ATP5B蛋白进行生物信息学分析。采用同源重组方法构建原核表达载体pGEX-4T-1-ATP5B-Flag和真核表达载体pcDNA3.0-ATP5B-Flag。以原核表达载体pGEX-4T-1-ATP5B-Flag转化大肠杆菌BL21感受态细胞,利用IPTG进行诱导表达,分析最适诱导温度和IPTG浓度。以真核表达载体pcDNA3.0-ATP5B-Flag转染HEK-293T细胞,通过Western blotting和间接免疫荧光试验(IFA)检测ATP5B蛋白在细胞中的表达及分布情况。【结果】 鼠源ATP5B基因CDS长1590 bp,鼠源ATP5B蛋白由529个氨基酸残基构成,分子量为55 kD,理论等电点(pI)为5.21,属于稳定的疏水性蛋白,无跨膜结构域和信号肽,不属于分泌蛋白;鼠源ATP5B蛋白二级结构中α-螺旋占43.67%,无规则卷曲占32.51%,β-转角占9.45%,延伸链占14.37%。原核表达载体pGEX-4T-1-ATP5B-Flag经IPTG诱导后,通过考马斯亮蓝染色和Western blotting在81 kD处成功检测到融合蛋白,且主要以包涵体形式表达,诱导条件以30℃、0.5 mmol/L IPTG的效果更好。以真核表达载体pcDNA3.0-ATP5B-Flag转染HEK-293T细胞后,在55 kD处检测到Flag标签特异性条带,即ATP5B蛋白在HEK-293T细胞中成功表达,IFA检测结果表明该蛋白主要定位在细胞质中。【结论】 成功构建鼠源ATP5B基因原核和真核表达载体,原核表达载体表达出的融合蛋白主要以包涵体形式存在,只有少量可溶蛋白,真核表达的ATP5B蛋白主要定位在细胞质中。鼠源ATP5B蛋白是理化性质稳定的疏水性蛋白,无信号肽位点,不属于分泌蛋白。

     

    Abstract: 【Objective】 The objective of this study was to clone the mouse ATP5B gene, and construct its prokaryotic and eukaryotic expression vectors, in order to provide a foundation for studying the function of ATP5B protein and its role mechanism in the process of viral infection. 【Method】 The coding region(CDS) of mouse ATP5B gene was cloned. Bioinformatics analysis of ATP5B protein was performed using ProtParam, ProtScale, and SignalP-5.0. Construction of prokaryotic expression vector pGEX-4T-1-ATP5B-Flag and eukaryotic expression vector pcDNA3.0-ATP5B-Flag was carried out by homologous recombination. The prokaryotic expression vector pGEX-4T-1-ATP5B-Flag was transformed into Escherichia coli BL21 competent cells, and IPTG was used for induction expression, the optimal induction temperature and IPTG concentration was analyzed. And the eukaryotic expression vector pcDNA3.0-ATP5B-Flag was transfected into HEK-293T cells. The expression and distribution of ATP5B protein in cells were detected by Western blotting and indirect immunofluorescence assay(IFA). 【Result】 The CDS of mouse ATP5B gene was 1590 bp, and the mouse ATP5B protein was composed of 529 amino acids residues, with a molecular weight of 55 kD. The theoretical isoelectric point(pI) was 5.21, it was a stable hydrophobic protein without transmembrane domains and signal peptides, and it was not a secretory protein. The secondary structure of mouse ATP5B protein included 43.67% α-helix, 32.51% random coil, 9.45% β-turn and 14.37% extended strand. After IPTG induction of the prokaryotic expression vector pGEX-4T-1-ATP5B-Flag, the fusion protein was successfully detected at 81 kD by Coomassie brilliant blue staining and Western blotting, mainly expressed in the form of inclusion bodies, with better induction conditions at 30 ℃ and 0.5 mmol/L IPTG. After transfection of HEK-293T cells with the eukaryotic expression vector pcDNA3.0-ATP5B-Flag, a Flag specific band was detected at 55 kD, confirming successful expression of the ATP5B protein in HEK-293T cells. The results from the IFA detection indicated that the protein was mainly located in the cytoplasm. 【Conclusion】 The prokaryotic and eukaryotic expression vectors of the mouse ATP5B gene are successfully constructed. The fusion protein expressed by the prokaryotic expression vector mainly exists in the form of inclusion bodies, with only a small amount of soluble protein. The eukaryotically expressed ATP5B protein is mainly localized in the cytoplasm. The mouse ATP5B protein is a stable hydrophobic protein with stable physicochemical properties, without signal peptide site, and is not a secretory protein.

     

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