Expression and characterization of human D4 dopamine receptors in baculovirus‐infected insect cells

Abstract

The human D4 dopamine receptor has been genetically engineered for expression in insect cells using the baculovirus system. A D4 cDNA gene fusion construct [(1991) Nature 350, 610-614] was synthetically modified to remove two introns from the coding region, and expressed in S. frugiperda (Sf9) cells as a fusion with a short sequence from the polyhedrin protein. Binding assays with [3H]spiperone indicated high levels of D4 receptor binding 90 h after infection and a pharmacological profile identical to that reported for D4 receptors expressed in COS-7 cells using the cDNA gene hybrid. We also show that the agonist binding affinity of D4 receptors expressed in Sf9 cells can be shifted by GTP-gamma-S, indicating coupling to G-proteins.