title: Molecular characterization of a new leucine-rich repeat-containing G protein-coupled receptor from a bivalve mollusc: evolutionary implications.
abstract: The family of leucine-rich repeat-containing G protein-coupled receptors (LGRs) shows members in both vertebrates and invertebrates including the most ancestral ones. Although this suggests an early evolutionary origin of this family of receptors, little is known about their diversity in molluscs, a major phylum of bilaterian invertebrates. Based on sequences of mammalian and insect LGRs, we have cloned and characterized a new typical LGR in the bivalve mollusc Crassostrea gigas. This receptor named Cg-LGRB exhibits high degree of amino acid sequence identity with both mammalian and Drosophila LGRs. Phylogenetic analysis indicates that Cg-LGRB belongs to the cluster of type B orphan LGRs and suggests that molluscs likely express the three LGR subgroups identified previously in other animals. Quantitative RT-PCR shows that Cg-LGRB is expressed mainly in the digestive gland and only at moderate levels in other organs and developmental stages. A possible involvement in the control of cytological changes occurring in bivalve mollusc digestive gland is discussed.
authors.affiliation: Laboratoire de Biologie et Biotechnologies Marines, IBFA, UMR IFREMER-Université de Caen, Physiologie et Ecophysiologie des Mollusques Marins, Esplanade de la Paix, 14032 Caen Cedex, France.
authors.forename: Amaury
authors.initials: A
authors.lastname: Herpin
authors.forename: Fabien
authors.initials: F
authors.lastname: Badariotti
authors.forename: Frank
authors.initials: F
authors.lastname: Rodet
authors.forename: Pascal
authors.initials: P
authors.lastname: Favrel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D004064:Digestive System / Q000378:metabolism; D007930:Leucine / Q000737:chemistry; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D008974:Mollusca / Q000737:chemistry*; D010802:Phylogeny; D011506:Proteins / Q000235:genetics*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins; D043562:Receptors, G-Protein-Coupled; D007930:Leucine