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Identification and characterization of a sex peptide receptor-like transcript from the western tarnished plant bug, Lygus hesperus

Hull, J. J., Brent, C. S.
Insect molecular biology 2014 v.23 no.3 pp. 301-319
Drosophila melanogaster, Helicoverpa armigera, Lygus hesperus, adults, chimerism, females, hindgut, insects, midgut, oviposition, peptides
Lygus hesperus females exhibit a post-mating behavioral switch that triggers increased egg laying and decreased sexual interest. In Drosophila melanogaster, post-mating changes in behavior are controlled by sex peptide (SP) and the sex peptide receptor (DmSPR). SPR is present in most insect genomes, but ligand specificity varies with myoinhibiting peptides (MIPs) identified as the ancestral ligand. Post-mating changes in Helicoverpa armigera that are mediated by SPR (HaSPR) suggest a pleiotropic receptor with some functional conservation. In this study, we identified a transcript, designated L. hesperus SPR (LhSPR), homologous to known SPRs that is expressed throughout development and most adult tissues. Relative qPCR indicated higher LhSPR abundance in female seminal depositories and heads as well as the hindgut/midgut of both sexes. Fluorescent chimeras of LhSPR, DmSPR, and HaSPR all localized to the cell surface of cultured insect cells but only DmSPR and HaSPR bound carboxytetramethylrhodamine-labeled analogs of previously characterized SPR ligands. Furthermore, injected DmSP21-36 had no effect on L. hesperus receptivity. Potential divergence in the LhSPR ligand-binding pocket may be linked to receptor-ligand co-evolution. A putative L. hesperus MIP precursor encodes multiple MIPs exhibiting a W-X7-W motif as opposed to the W-X6-W and W-X8-W motifs of most MIPs and SP.