BACKGROUND:The hyperpoladzation-activated cyclic nucleotide-gated cation channel (HCN) gene is not increase the risk of induced cardiac arrhythmia,and can accept the modulation function of autonomic nervous system.Therefore,it is the first candidate gene for biological pacemakers.OBJECTIVE:To construct recombinant adenovirus vector containing human HCN4 gene and evaluate its transfection efficency in rat bone marrow mesenchymal stem cells (MSCs).DESIGN,TIME AND SETTING:The in vitro cytology-gene experiment was performed at the Lin Bai-xin Experimental Center,Second Hospital of Sun Yat-sen University from February to September 2008.MATERIALS:Ten SD rats were supplied by the experimental animal center of Sun Yat-sen University.Rlasmid pcDNA3.1-HCN4 containing target gene human HCN4,human embryo kidney 293 cells and Escherichia coll DH5α were preserved by our experimental center;Shuttle plasmid pShuttle-CMV containing green fluorescent protein gene and adenoviral backbone plasmid pAdxsi were bought from SinoGenoMax Co.,Ltd.METHODS:HCN4 cDNA segment was liberated from the cloning vector of pcDNA3.1-HCN4 via Hind Ⅲ+Xba Ⅰ,and subcloned into pShuttle-CMV,which was digested by I-Ceu Ⅰ +I-Sce Ⅰ double enzyme and subcloned into adenoviral plasmid to form recombinant adenovirus plasmid.Recombinant adenovirus plasmid was transfected into 293 cell lines by liposome,and the recombinant adenovirus AdHCN4 was packaged and transfected into rat MSCs.MAIN OUTCOME MEASURES:The identification of recombinant adenovirus plasmid vector,identification of recombinant adenovirus and its titration test;the transfection efficiency of recombinant adenovirus.RESULTS:Cloned sequence about 3.6kbp was obtained by Hind Ⅲ+Xho Ⅰ digestion after HCN4 cDNA segment was cloned into pShuttle-CMV.DNA sequencing results indicated that the clone location was correct.Recombinant adenovirus plasmid was cut into seven fragments while empty vector gained only six fragments after digested by Xho Ⅰ.The recombinant adenovirus was pathogenic to 293 cells after recombinant adenovirus plasmid was packaged in it.HCN4 cDNA (657bp) was amplified by PCR with virus titer of 2.5×10~(11) PFU/mL after transfected 293 cells with supematant.The efficiency of recombinant adenovirus infecting rat MSCs was about 90% when multiplicity of infection was 800.Rat MSCs expressed green fluorescence after transfection.CONCLUSION:The adenovirus vector with human HCN4 cDNA was established successfully,which can effectively transfect rat MSCs.