Insect-vertebrate chimeric nicotinic acetylcholine receptors identify a region, loop B to the N-terminus of the Drosophila Dalpha2 subunit, which contributes to neonicotinoid sensitivity.
A chimera based on the chicken alpha4 nicotinic acetylcholine receptor (nAChR) subunit containing an insert from loop B to the N-terminus of the Drosophila melanogaster Dalpha2 (=SAD) subunit was constructed and co-expressed with the chicken beta2 nAChR subunit in Xenopus laevis oocytes. The actions of the neonicotinoid insecticide imidacloprid were examined. Replacement of the region loop B to the N-terminus of the alpha4 subunit by the corresponding region of the Dalpha2 subunit had little effect on the concentration-response curve for imidacloprid. However, replacement of Glu219 by proline in the YXCC motif in loop C of the chimeric alpha4 subunit resulted in a marked displacement to the left of the concentration-response curve for imidacloprid not seen when an equivalent mutation was made in the alpha4beta2 nAChR. The results suggest that the region loop B to the N-terminus in the Dalpha2 subunit contributes to the high imidacloprid sensitivity of the hybrid Dalpha2beta2 nAChR.
Shimomura
Masaru
M
Department of Applied Biological Chemistry, School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
Satoh
Hitoshi
H
Yokota
Maiko
M
Ihara
Makoto
M
Matsuda
Kazuhiko
K
Sattelle
David B
DB
D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence / Q000502:physiology; D019943:Amino Acid Substitution / Q000502:physiology; D000818:Animals; D002645:Chickens; D018678:Cholinergic Agents / Q000494:pharmacology; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004351:Drug Resistance / Q000235:genetics; D007093:Imidazoles / Q000494:pharmacology*; D000073943:Neonicotinoids; D009574:Nitro Compounds; D009865:Oocytes; D017434:Protein Structure, Tertiary / Q000502:physiology; D021122:Protein Subunits / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000187:drug effects / Q000235:genetics; D014982:Xenopus laevis
D018678:Cholinergic Agents; D007093:Imidazoles; D000073943:Neonicotinoids; D009574:Nitro Compounds; D021122:Protein Subunits; D011978:Receptors, Nicotinic; D011993:Recombinant Fusion Proteins; C082359:imidacloprid