Prediction and expression analysis of G protein-coupled receptors in the laboratory stick insect, Carausius morosus

Abstract

G protein-coupled receptors (GPCRs) are 7-transmembrane proteins that transduce various extracellular signals intointracellular pathways. They are the major target of neuropeptides, which regulate the development, feeding behavior, mating behavior,circadian rhythm, and many other physiological functions of insects. In the present study, we performed RNA sequencing and denovo transcriptome assembly to uncover the GPCRs expressed in the stick insect Carausius morosus. The transcript assemblies werepredicted for the presence of 7-transmembrane GPCR domains. As a result, 430 putative GPCR transcripts were obtained and 43 ofthese revealed full-length sequences with highly significant similarity to known GPCR sequences in the databases. Thirteen differentGPCRs were chosen for tissue expression analysis. Some of these receptors, such as calcitonin, inotocin, and tyramine receptors, showedspecific expression in some of the tissues. Additionally, GPCR prediction yielded a novel uncharacterized GPCR sequence, which wasspecifically expressed in the central nervous system and ganglia. Previously, the only information about the anatomy of the stick insectwas on its gastrointestinal system. This study provides complete anatomical information about the adult insect.