Cloning and characterization of a GABA receptor from Plutella xylostella (Lepidoptera: Plutellidae).
A full-length cDNA, with an open reading frame (ORF) of 1,449 bp, encoding a subunit of the gamma-aminobutyric acid (GABA)-activated chloride channel was isolated from Plutella xylostella (L.) (Lepidoptera: Plutellidae) (GenBank accession no. EF156251). The subunit gene encoded a 483-amino acid polypeptide that showed 84% sequence identity with DmRdl subunit (U02042) (Drosophila melanogaster resistant to dieldrin). When expressed in Xenopus laevis oocytes, the subunit assembled as a functional homomeric complex activated by GABA and abamectin in a dose-dependent manner. The EC50 value of GABA was 0.49 mM (0.41-0.58) (n = 5). However, the responses to abamectin were very robust, with an EC50 of 4.85 microM (4.02-5.89) (n = 6), indicating that abamectin was > 100-fold more potent in activating chloride currents than GABA. The results suggest that this subunit is vital to the formation of a functional channel and contains the binding site of abamectin.
Zhou
Xiao-Mao
XM
Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie, Beijing 100081, China.
Wu
Qing-Jun
QJ
Zhang
You-Jun
YJ
Bai
Lian-Yang
LY
Huang
Xiong-Ying
XY
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004553:Electric Conductivity; D019476:Insect Proteins / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D007306:Insecticides / Q000494:pharmacology*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000494:pharmacology; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics*; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D018079:Receptors, GABA / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D016415:Sequence Alignment; D014981:Xenopus; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D019476:Insect Proteins; D007306:Insecticides; D018079:Receptors, GABA; D005680:gamma-Aminobutyric Acid; C048324:abamectin; D007559:Ivermectin