NF-κB结合位点在NOD2基因调控中的作用

The role of NF-κB binding element in regulation of NOD2 gene

目的探讨NF-κB结合位点在NOD2基因调控中的作用。方法以人基因组DNA为模板，PCR扩增含有NF-κB结合位点的人NOD2基因启动子序列，以切除启动子的pEGFP-N3作为框架结构，将这段序列进行酶切并定向克隆人表达载体pEGFP-N3中，构建含有NF-κB结合位点的人NOD2基因启动子驱动的绿色荧光蛋白（GFP）载体，将构建的重组质粒经脂质体LipofectAMINE^TM 2000介导瞬时转染HeLa细胞，在倒置荧光显微镜下观察其能否在NOD2基因启动子的调控下表达报告基因GFP。用突变试剂盒将重组质粒pEGFP-N3-NOD2wt中的NF-κB结合位点缺失突变，将构建的突变重组质粒mpEGFP-N3-NOD2瞬时转染HeLa细胞，观察绿色荧光蛋白的表达情况。结果pEGFP-N3-NOD2wt和mpEGFP-N3-NOD2经酶切鉴定和序列测定证实重组质粒构建成功，并且NF-κB结合位点突变成功。细胞转染结果表明，构建的重组质粒pEGFP-N3-NOD2wt转染HeLa细胞，在倒置荧光显微镜下能看到绿色荧光，而突变质粒mpEGFP-N3-NOD2荧光强度明显减弱，与未转染质粒相近。结论成功构建了含有NF-κB结合位点的人NOD2基因启动子的重组质粒和含有NF-κB结合位点缺失突变的重组质粒；NF-κB结合位点突变重组质粒在HeLa细胞中绿色荧光表达明显减弱，说明NF-κB结合位点在NOD2基因调控中发挥了正调节作用；为进一步研究NOD2基因表达及调控机制奠定了良好的基础。

Objective To investigate the role of NF-κB binding element in regulation of NOD2. Methods Promoter region of NOD2 containing the NF-κB binding site was amplified by PCR from human genome DNA and correctly connected to the vector pEGFP-N3 which had been cut out promoter by restriction enzyme to obtain the GFP expression vector driven by human NOD2 gene promoter. The constructed plasmids were transiently transferred into cell line HeLa by LipofectAMINE^TM2000 and the GFP expression was observed by the inversion fluorescence microscope. The NF-κB binding site in the constructed vector pEGFP-N3-NOD2wt was deleted by the QuikChange site-directed mutagenesis kit. The recombinant plasmid mpEG-FP-N3-NOD2 was transiently transferred into cell line HeLa by LipofectAMINE^TM2000, and the GFP expression was observed by the inversion fluorescence microscope. Results The constructed pEGFP-N3-NOD2wt plasmids and mpEGFP-N3-NOD2 were the same as the design confirmed by restriction digestion and sequence analysis. The results of the cell transient transfection indicated that different strength of GEP expressed by recombinant plasmids in HeLa cells could be observed. The GFP expression of constructed mpEGFP-N3-NOD2 was lower than that of pEGFP-N3-NOD2wt. Conclusion The GFP expression vector driven by human NOD2 gene promoter which contains the NF-κB binding site, and the site deleted plasmid were successfully constructed. The GFP expression of recombinant plasmid mpEGFP-N3-NOD2, deletion of the NF-κB binding site, was obviously weaken in HeLa. The results indicate that NF-κB binding element may play a positive role in regulation of NOD2 gene, which establishes favourable bases for further study on the mechanism of NOD2 gene expression and regulation.