Cox7a2荧光载体构建及其对小鼠支持细胞细胞色素C氧化酶活性的影响

Construction of Cox7a2 fluorescent vector and its effect on cytochrome C oxidase activity in mouse Sertoli cell line TM4

目的构建pEYFP-Cl-Cox7a2表达载体，研究其在小鼠睾丸支持细胞（TM4）中的表达及对细胞色素C氧化酶（COX）活性的影响。方法应用RT—PCR方法从TM4细胞克隆Cox7a2，利用BamHI和EcoRI酶切位点将Cox7a2克隆到pEYFP—C1载体，经酶切、测序及蛋白印迹等技术进行鉴定，并将重组质粒pEYFP—C1-Cox7a2转染TM4细胞后6、12、24、48h，采用分光光度计测定COX活性。结果从TM4细胞克隆到Cox7a2基因完整的编码序列，大小为252bp。构建pEYFP—CI．Cox7a2表达载体，经酶切、测序鉴定证实克隆正确，转染TM4细胞的效率达70％，融合蛋白表达产物相对分子质量为37000。重组质粒转染后6、12、24、48h时COX活性分别为（0．642±0．051）、（0．542±0．049）、（0．311±0．021）和（0．216±0．010）U／mg，不转染组和转染空载体组分别为（0．714±0．064）、（0．653±0．031）U／mg。与不转染组相比，重组质粒转染后12、24、48h组COX活性显著降低（P〈0．05）。结论重组质粒pEYFP—Cl-Cox7a2载体成功构建。CoxTa2基因对TM4细胞COX活性具有抑制作用，可能对调控COX活性发挥重要作用。

Objective To construct Cox7a2 fluorescent vector and study its effect on cytochrome C oxidase （COX） activity in mouse Sertoli cell line TM4. Methods The coding region of CoxTa2 was amplified from mouse Sertoli cell line TM4 by RT-PCR. The PCR product was inserted into pEYFP-Cl vector with BamH I and EcoR I restriction site, and confirmed by DNA sequencing. The recombinant fusion protein vector was amplified by transforming into DH5a and transfected into TM4 cells. The protein expression was identified by Western blot. COX activity was measured by spcctrophotometer 6, 12, 24 and 48 h after the transfection of recombinant vector into the TM4 cell line. Results The entire coding sequence of CoxTa2 was cloned with 252 bp length. Plasmid pEYFP-Cl-CoxTa2 vector was constructed and the positive clones were verified by restriction enzymes digestion and DNA sequencing. The transfection efficiency of the TM4 cell line was about 70% and 37000 D fusion protein was obtained. The COX activities were （0. 642 ± 0,051）, （0.542 ±0.049）, （0.311 ±0.021） and （0.216±0.010） U/rag6, 12, 24 and 48 h after the transfection of recombinant vector in the TM4 cell line. Meanwhile, the COX activities were （0. 714± 0. 064） and （0. 653± 0. 031 ） U/rag in non-tranfeeted and naked vector group respectively. Compared with the non-tranfeeted group, COX activity decreased significantly 12, 24 and 48 h after the transfection. Conclusions The recombint plasmid vector was successfully constructed. Cox7a2 gene has an inhibiting effect on COX activity and may play an important role in the regulation of COX activity in mouse Sertoli cell line TM4.