目的:构建一种能够验证内部核糖体进入位点的双荧光素酶报告载体，为验证内部核糖体进入位点(internal ribosome entry site, IRES)活性提供了方法。方法:以双荧光素酶报告基因载体psiCHECK-2为基础，将发卡结构插入到海肾荧光素酶(R-Luc)基因与萤火虫荧光素酶(F-Luc)基因之间，构建载体psiCHECK-IRES。为了验证载体是否有效，通过同源重组技术将Encephalomyocarditis virus(EMCV)的IRES序列插入到psiCHECK-IRES载体的发卡结构与F-Luc之间，形成载体psiCHECK-IRES-EMCV。以psiCHECK-2质粒做模板建立F-Luc与R-Luc的扩增标准曲线。将psiCHECK-IRES与psiCHECK-IRES-EMCV质粒转染BHK-21细胞，利用RT-qPCR检测F-Luc与R-Luc的拷贝数；将psiCHECK-IRES与psiCHECK-IRES-EMCV质粒分别转染BHK-21细胞，24 h后利用双荧光素酶报告基因检测系统检测荧光素酶活性。结果:经过测序证实带有发卡样结构的双荧光素酶表达载体psiCHECK-IRES的载体序列。RT-qPCR结果显示F-Luc与R-Luc mRNA的拷贝数大致相同，证明未出现异常的单顺反子转录本，避免F-Luc读数出现假阳性；插入EMCV IRES的psiCHECK-IRES-EMCV载体表达的F-Luc/R-Luc比值是空载体的53.35倍，证明EMCV的IRES序列能够在构建的载体上起始F-Luc基因的表达。结论:本研究构建了可用于验证病毒或者细胞依赖IRES表达的双荧光素酶报告载体psiCHECK-IRES。“,”Objective:To construct the dual-luciferase reporter vector for identification of internal ribosome entry site (IRES).Methods:The hairpin structure was inserted between Renilla luciferase (R-Luc) and Firefly luciferase (F-Luc) genes based on psiCHECK-2 to form plasmid psiCHECK-IRES. IRES of Encephalomyocarditis virus (EMCV) was inserted between the hairpin structure and F-Luc genes of psiCHECK-IRES to form vector psiCHECK-IRES-EMCV. After psiCHECK-IRES-EMCV or psiCHECK-IRES was transfected into BHK-21 cells respectively, expressions of F-Luc and R-Luc were detected by RT-qPCR. Then Luciferase activity of transfected cells was detected with the dual-luciferase reporter assay system at 24 h post-transfection.Results:The hairpin structure was successfully inserted into psiCHECK-2 to form psiCHECK-IRES by sequencing. RT-qPCR result showed that there were the approximate expressing levels of mRNA between F-Luc and R-Luc. The result indicated that no aberrant monocistronic transcripts, which caused false positive F-Luc readings, were produced. Then IRES of EMCV was introduced into psiCHECK-IRES to form psiCHECK-IRES-EMCV. The F-Luc/R-Luc ratio in psiCHECK-IRES-EMCV-transfected cells was 53.35 times that of psiCHECK-IRES-transfected cells. The result confirmed that IRES of EMCV initiated effectively the translation of F-Luc.Conclusions:Dual-luciferase reporter vector psiCHECK-IRES was successfully constructed, which could be used to validate viruses and eukaryotic genes, the translation thereof was IRES-dependent.