Abstract: Objective: To clone rat GAP-43 gene and express it in mammalian cells.Methods: RT-PCR was used to amplify rat GAP-43 gene from RNA of rat oligodendrocyte precursor cells(OPCs).The GAP-43 gene was inserted into eukaryotic expression vector pEGFP-N3.The recombinant expression vector was transiently transfected into COS-7 cells by Lipofectamine^TM 2000 reagent.The expression of GAP-43 in COS-7 cells was detected by immunocytochemistry.Results: The sequence of the cloned GAP-43 was confirmed to be correct by DNA sequencing.The COS-7 cells transfected with pEGFP-N3-GAP-43 expressed GAP-43 protein efficiently.Conclusions: The cloning of rat GAP-43 gene and the construction of its eukaryotic expression vector were successful,which lays the foundation for further investigating the role of GAP-43 in development of oligodendrocytes.