Molecular cloning and expression analysis of octopamine receptor gene in pearl oyster (Pinctada fucata)

Octopamine receptor (OAR) is common in invertebrates and plays an important role in invertebrate life, including adjusting nerve muscle rhythm contraction and the cAMP level, participating in phosphorylation pathways, etc.. However, there is little research on the OAR gene in mollusks. In this study, we cloned an OAR gene from pearl oyster (Pinctada fucata) to investigate the characteristics of the cDNA and deduced amino acid sequences, relative expression levels in different tissues and development stages using qPCR, as well as the relative expression levels after shell damage. The results show that the full length cDNA of pfOAR was 1 890 bp, with 1 659 open reading frame (ORF), encoding 552 amino acids. The pfOAR had common features of the vast family of G protein-coupled receptors including seven hydrophobic transmembrane domains. The qPCR analysis reveals ubiquitous expression of pfOAR mRNA in all six tissues, with significantly high expression level in mantle tissue and at metamorphosis stage during larval development. Furthermore, the relative expression level reached the maximum in 36 h after shell notching. It is conluded that pfOAR might play various roles in P.fucata, including possible involvement in the formation and repairment of the shell, which provides references for further functional study of pfOAR.