RESUMO
Objective To obtain the fusion genes of several human orphan G protein coupled receptors (oGPCRs) with Gi1α subtype of G protein and their expression system. Methods The whole open reading frames of GPR45, GPR85, GPR174 and Gilα were cloned by RT-PCR from HepG2 cDNA separately,and the corresponding fusion genes were amplified by overlap extension PCR. Then, the fusion genes-containing pBacmids were successfully constructed with the Bac-to-Bac baculovirus expression system indicated by specific transposition and virus recombination. The insect Sf9 cells were transfected with pBacmid-oGPCRs-Gi1α, and the supernatant containing recombinant virus was harvested. With the supernatant, insect Sf9 cells were infected under an optimized condition (MOI=5, infection time=72 h) and the fusion proteins were prepared and detected by Western blotting.Results The three fusion genes of GPCR45, GPR85 or GPR174 with Gi1α were obtained. The corresponding fusion proteins could be properly prepared in Sf9 cells.Conclusion Human oGPCRs could be fused with Gilα, and the fusion genes could be expressed using the Bac-to-Bac baculovirus expression system in insect Sf9 cells.