|Nachman, Ronald - Ron|
Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/15/2002
Publication Date: 11/26/2002
Citation: Meeusen, T., Mertens, I., Clynen, E., Baggerman, G., Nichols, R., Nachman, R.J., Huybrechts, R., Deloof, A., Schoofs, L. 2002. Identification of Drosophila of the invertebrate G-protein couples FMRFamide receptor. Proceedings of the National Academy of Sciences. 99:15363-15368. Interpretive Summary: Neuropeptides are short chains of amino acids (the building blocks of proteins) that regulate aspects of reproduction, development and digestion that are critical for insect survival. Nevertheless, these insect peptides in and of themselves hold little promise as insect control agents because of susceptibility to being degraded in the target insect, and inability to pass through the outside skin (cuticle) and/or digestive tract of the insect. We must design neuropeptide mimics that resist degradation by enzymes in the digestive tract and blood of pest insects and enter efficiently via a topical or oral route. We report on the first isolation and identification of the active site for the FMRFamide class of neuropeptides from an insect. This information will aid in the development of enzyme-resistant FMRFamide neuropeptide mimics capable of disrupting neuropeptide-regulated processes in insects. The work brings us one step closer to the development of practical neuropeptide-like substances that will be effective in controlling pest insects in an environmentally friendly fashion.
Technical Abstract: We here describe the cloning and characterization of the functionally active Drosophila melanogaster (Drm) FMRFamide receptor, which we designated as DrmFMRFa-R. The full-length ORF of a D. melanogaster orphan receptor CG 2114 (Berkeley Drsophila Genome Project), was cloned from genomic DNA. This receptor is distantly related to mammalian TSH-releasing hormone receptors and to a set of Caenorhabditis elegans orphan receptors. An extract of 5,000 central nervous systems from the related but bigger flesh fly, Neobellieria bullata (Neb), was used to screen cells expressing the orphan receptor. Successive purification steps, followed by mass spectrometry, revealed the sequence of two endogenous peptides, APPQPSDNFIRFamide (Neb-FIRFamide) and pQPSQDFMRFamide (Neb-FMRFamide). These are remniscent of other insect FMRFamide peptides, having neurohormonal as well as neurotransmitter functions. Nanomolar concentrations of the D. melanogaster FMRFamides (DPKQDFMRFamide; TPAEDFMRFamide; SDNFMRFamide; SPKQDFMRFamide; PDNFMRFamide) activated the cognate receptor in a dose-dependent manner. To our knowledge, the cloned DrmFMRFa-R is the first functionally active FMRFamide G-protein coupled receptor described in invertebrates to date.