Macrophage inflammatory protein-3α (MIP-3α or CCL20),a member of the chemokine family,plays an important role in the immune response.In this study,the Mauremys mutica CCL20 (Ma CCL20) cDNA sequence was initially obtained by screening the constructed full-length cDNA library and were verified by gene cloning method.Then the structure and function of the MaCCL20 gene were predicted by using software and the gene expression in different tissues was analyzed by using real-time quantitative PCR.The results showed that the full-length cDNA of MaCCL20 gene is 2 318 bp,containing a 261 bp open reading frame and encoding 86 amino acids.The MaCCL20 protein is hydrophobic and has no trans-membrane structure.Homology analysis indicated that the MaCCL20 shared high similarity with Anolis carolinensis,followed by Gallus gallus and shared the lowest similarity with mammalian.Real-time PCR results showed that the MaCCL20 gene was highly expressed in the spleen and was also expressed in other tissues including liver,kidney and heart.The study laid a foundation for further research of the function of MaCCL20.