Objective To construct the recombinant plasmid pEGFP-N1-SrV+ and evaluate the expression of SrV+in mammalian 293T cells.nethods srv+.a gene encoding the vailable region of the surface protein of the Streptococcus mutans OMZ175.was cloned chemically based on its reported nucleotide sequence.The eukaryotic expression plasmid,pEGFP-N1-SrV+,was constructed by introducing the srv+ gene into the Kpn Ⅰ/Xho Ⅰ site of pEGFP-NI.The recombinant plasmid pEGFP-N1-SrV+was transfected into 293T cells with lipofectamine and the expression level of SrV+was evaluated.Results The eukaryotic expression plasmid pEGFP-N1-SrV+was constructed successfully.GFP was observed by green fluorescent microscope.and a 72 × 1 03 protein was detected bv Westem blot.Real-time RT-PCR analysis revealed that the expression of the pEGFP-N1-SrV+in 293T was excellent and significant compared the control group. Conclusion The recombinant plasmid pEGFP-N1-SrV+was successfully constructed.which could encode the expression of SrV+after transfected into the mammalian 293T Cells.