Functional expression and ligand identification of homo- and heteromeric \(\textit {Drosophila melanogaster}\) \(CO_2\) receptors in the \(\textit {Xenopus laevis}\) oocyte system

  • Carbon dioxide (\(CO_2\)) is an important olfactory cue in \(\textit {Drosophila melanogaster}\) and can elicit both attractive and aversive behaviors. It is detected by gustatory receptors, Gr21a and Gr63a, found in the ab1C neuron in basiconic sensilla on the third antennal segment. Volatile substances that modulate the receptors’ function are of interest for pest control. While several substances block ab1C neurons or mimic the activating effect of carbon dioxide, it is not known if these substances are indeed ligands of the \(CO_2\) receptor or might act on other proteins in the receptor neuron. In this study, we used the recombinant \(\textit {Xenopus laevis}\) expression system and two-electrode voltage-clamp technology to investigate the receptor function. We found that application of sodium bicarbonate evokes large inward currents in oocytes co-expressing Gr21a and Gr63a. The receptors most likely form hetromultimeric complexes. Homomultimeric receptors of Gr21a or Gr63a are sufficient for receptor functionality, although oocytes gave significantly lower current responses compared to the probable heteromultimeric receptor. We screened for putative blockers of the sodium bicarbonate response and confirmed that some of the substances identified by spike recordings of olfactory receptor neurons, such as 1-hexanol, are also blockers in the \(\it Xenopus\) oocyte system. We also identified a new blocking substance, citronellol, which is related to insect repellents. Many substances that activate receptor neurons were inactive in the \(\it Xenopus\) oocyte system, indicating that they may not be ligands for the receptor, but may act on other proteins. However, methyl pyruvate and n-hexylamine were found to be activators of the recombinant Gr21a/Gr63a receptor.

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Author:Paul Michael ZiembaGND, Alina MückGND, Günter GisselmannGND, Klemens F. StörtkuhlORCiDGND
Parent Title (English):PLoS ONE
Publisher:Public Library of Science
Place of publication:San Francisco
Document Type:Article
Date of Publication (online):2024/04/15
Date of first Publication:2023/12/29
Publishing Institution:Ruhr-Universität Bochum, Universitätsbibliothek
Tag:Open Access Fonds
Issue:12, Artikel e0295404
First Page:e0295404-1
Last Page:e0295404-15
Article Processing Charge funded by the Deutsche Forschungsgemeinschaft (DFG) and the Open Access Publication Fund of Ruhr-Universität Bochum.
Institutes/Facilities:Fakultät für Biologie und Biotechnologie, Arbeitsgruppe Sinnesphysiologie
Dewey Decimal Classification:Naturwissenschaften und Mathematik / Biowissenschaften, Biologie, Biochemie
open_access (DINI-Set):open_access
faculties:Fakultät für Biologie und Biotechnologie
Licence (English):License LogoCreative Commons - CC BY 4.0 - Attribution 4.0 International