Molecular Characterization of G‐proteins in bluegill

Abstract

The focus of research in our laboratory is directed towards understanding pigment granule dispersion of bluegill (Lepomis macrochirus) retinal pigment epithelium (RPE) and the role of muscarinic receptors in the signaling pathways of pigment granule dispersion. Muscarinic receptors belong to the G-protein coupled receptor (GPCR) superfamily. Binding of muscarinic receptors by acetylcholine or carbachol activates the G-protein coupled to it, causing a cascade of events that lead to dispersion of pigment granules in RPE. To better understand this signaling pathway, an attempt was made to molecularly characterize G-proteins from cDNA extracted from brain and heart of bluegill. Database screening yielded Gαq, Gα11 and Gαi sequences from different organisms. Primers were designed based on highly conserved domains of these genes in all organisms. PCR was used to amplify the cDNAs and the products were sequenced. So far, we have successfully amplified 893bp and 692bp of the expected 1080bp of bluegill Gαq and Gα11 respectively, and 793bp of the expected 1065bp of bluegill Gαi. Future studies will be directed towards finding the expression of these G-proteins in different tissues and their function in carbachol-induced pigment granule dispersion in bluegill RPE.