Abstract:Abstract: [Objective] Purified avian influenza virus (AIV) hemagglutinin (HA) gene fragment was inserted into green fluorescent protein (GFP) expression vector, pEGFP-C1. The role of signal peptide in the HA-GFP expression in 293T cells was investigated by cutting the signal peptide or placing it in different locations of HA-GFP fusion gene. [Methods] The expression of GFP in 293T cells was examined directly with fluorescence microscope and flow cytometry analysis. [Results] After transfected with pEGFP-C1, M1, M2 and M3 plasmid, under fluorescent microscope the HA-GFP fusion protein was successfully expressed. Fluorescence was seen homogeneously distributed in the entire cell body of the cells transfected by the empty vector pEGFP-C1, whereas signal peptide could obviously reduced the expression of GFP-HA compared with recombinant plasmid without signal peptide. In addition, we found that there was no significant effect of the location of signal peptide on the expression of HA-GFP fusion protein.