Abstract: OBJECTIVE: The insect baculovirus expression system was used to express the early rapid response gene 5 protein,and to provide clues for subsequent protein crystallization and exploration of tertiary protein structure. METHODS: The recombinant transfer vector pFastBac1-IER5 was constructed via amplification of the IER5 gene fragment with HeLa cell cDNA as template. After confirmation by restriction enzyme digestion and DNA sequencing,the recombinant transfer vector was transformed into E.coli DH10BacTM competent cells to obtain the recombinant shuttle vector rBacmid-IER5. The recombinant shuttle vector was transfected into Sf9 cells and the recombinant baculovirus was collected when the cells showed obvious lesions. The expression products were analyzed and identified using indirect immunofluorescence,SDS-PAGE and Western blot. RESULTS: The expected two bands were observed after the recombinant transfer vector pFastBac1-IER5 was digested by restriction enzymes;a band with the excepted size of about 3300 bp was obtained from the recombinant shuttle vector rBacmid-IER5 by PCR amplification;the results from indirect immunofluorescence indicate that IER5 protein was expressed correctly in the Sf9 cells. The SDS-PAGE analyses reveal that the molecular weight of the expressed product was about 48k. The Western blot analyses show that the expressed product specifically reacted with the IER5 antibody. CONCLUSION: The recombinant IER5 protein from human was expressed successfully using the insect baculovirus expression system,and revealed the physical and chemical properties of the recombinant IER5 protein,like the molecular weight and dissolubility.

Key words: IER5, Sf9 cell, insect baculovirus expression system, identification