Objective To construct the bait expression plasmid pGBKT7-GR of glucocorticoid receptor (GR) binding domain.   Methods The fragments of GR binding domain was amplified by RT-PCR

and then was cloned into pMD18-T. After being verified by sequencing

it was subcloned into the bait expression vector pGBKT7. Then the bait vector pGBKT7-GR was transformed into AH109 yeast cells and the expression of the bait protein was analyzed by Western blot. Toxicity and self-activation of the bait protein were detected.   Results GR binding domain was amplified and cloned into pMD18-T and pGBKT7 successfully. The bait vector was transformed into AH109 yeast cells successfully

without toxicity or self-activation. The expression of the bait protein was confirmed by Western blot.   Conclusion The successful construction of bait expression vector of glucocorticoid receptor binding domain lays the foundation for constructing small molecule ligand yeast three-hybrid system.