Objective   To construct the eukaryotic expression vector for homo sapiens retinoic acid induced 16 (RAI16) fused with the enhanced green fluorescent protein (EGFP) and explore the expression of the fusion protein RAI16-EGFP in HepG2 cells．    Methods   The intact RAI16 sequence was fished and amplified from the plasmid clone templates containing RAI16 sequence fragment by PCR．Then it was inserted into the pEGFP-C1 vector to construct the recombinant eukaryotic expression vector pEGFP-C1-RAI16. The expression of the fusion protein RAI16-EGFP was detected after the transfection of pEGFP-C1-RAI16 into the HepG2 cells. The subcellular localization of RAI16 and expression of RAI16-EGFP were observed by confocal fluorescence microscopy and Western blotting.    Results   The pEGFP-RAI16 recombinant expression vector

with RAI16 was exactly inserted in pEGFP-C1

was constructed and confirmed by DNA sequencing

enzymatic digestion and PCR identification. In 24 h after the recombinant vector of fusion protein RAI16-EGFP was transfected into the cells

it was observed mainly in the cytoplasm. Western blot analysis showed the expression of RAI16 was up-regulated apparently at protein level after the cells were transfected with pEGFP-RAI16 for 24

48 or 72 h. While

at the same time

the protein expression of AFP was decreased.    Conclusion   The pEGFP-C1-RAI16 eukaryotic expression vector is successfully constructed

and the fusion protein RAI16-EGFP is expressed in the HepG2 cells after transfection.