Stable expression and characterisation of a human α7 nicotinic subunit chimera: a tool for functional high-throughput screening

Abstract A chimera comprising the N-terminal region of the human α7 nicotinic acetylcholine receptor, fused to the transmembrane/C-terminal domains of the mouse serotonin 5-HT 3 receptor, was constructed. Injection of the chimera cDNA into Xenopus oocytes, or transient transfection in human embryonic kidney (HEK-293) cells, resulted in the expression of functional channels that were sensitive to nicotinic acetylcholine, but not serotonin receptor ligands. In both systems, the responses obtained from chimeric receptors inactivated more slowly than those recorded following activation of wild-type α7 receptors. A stable HEK-293 cell line expressing the human α7/mouse 5-HT 3 chimera was established, which showed that the chimera displayed a similar pharmacological profile to wild-type α7 receptors. Use of this chimera in high-throughput screening may enable the identification of novel pharmacological agents that will help to define further the role of α7 nicotinic receptors in physiology and disease.