Functional integrity of honeybee (Apis mellifera L.) RDL GABA receptor channels conjugated with three fluorescent proteins.

To generate an efficient tool used in Xenopus oocyte expression for in situ investigation of channel receptor expression, distribution, and function, the C-terminus of the honeybee (Apis mellifera L.) resistant to dieldrin (RDL) subunit was fused with monomeric red, enhanced yellow, or enhanced green fluorescent protein (referred to as mRFP, EYFP, and EGFP, respectively). In the present study, all fused *FP-AmRDL could be visualized using fluorescence and laser confocal microscopy in cRNA-injected oocytes. Fluorescence was distributed isotropically in the cellular membrane. The potencies of the agonist GABA, but not β-alanine, and the antagonists (fipronil, flufiprole, dieldrin, α-endosulfan, bifenazate, and avermectin B1a) in the tagged AmRDL receptor did not significantly differ from that of the untagged receptor with two-electrode voltage clamp detection. The EC50 s of GABA in untagged AmRDL, EGFP-AmRDL, EYFP-AmRDL, and mRFP-AmRDL receptors were 11.98, 12.61, 18.92, and 22.11μM, respectively, and those of β-alanine were 651.6, 629.6, 1643.0, and 2146.0 μM, respectively. Inhibition percentages of fipronil, flufiprole, dieldrin, α-endosulfan, bifenazate, and avermectin B1a against *FP-AmRDL and AmRDL were without significant difference. Overall, the consistency in the functional properties between *FP-AmRDL and untagged AmRDL receptors makes it a promising tool for further in situ investigation of GABA receptors. This article is protected by copyright. All rights reserved.