Objective  To construct pGEX4T-1-RGS4 and detect the GST-RSG4 fusion protein expressed in Escherichia coli.   Methods  The cDNA of RGS4 was amplified from total RNA extracted from the liver issue of SD rat by RT-PCR and inserted into pGEX4T-1 vector. The GST-RSG4 fusion protein was induced by IPTG and its expression level was analyzed by Western blot.   Results  The pGEX4T-1-RGS4 vector was successfully constructed. Under the induction of IPTG

the RGS4 and GST expressed efficiently in the mode of fusion protein. The molecular weight of pGEX4T-1-RGS4 expressed in E. coli was 50 000

consistent with the expectation.    Conclusion  The recombinant plasmid expressed efficiently in E. coli. This is the first step for studying the relationship between RGS4 and the structure domains of GR though GST-pulldown method.