RESUMO
A gonadotropin receptor was cloned from amago salmon (Oncorhynchus rhodurus) ovarian follicles. This receptor (sGTH-R) belongs to the glycoprotein hormone receptor family with a large extracellular and seven-transmembrane domains. Its sequence homology is highest with mammalian LH receptors. Phylogenetic analysis reveals that sGTH-R is grouped with mammalian and chicken FSH and LH receptors, but not with mammalian TSH receptors. sGTH-R is expressed dominantly in the ovary and testis. Functional characterization examined with transiently transfected mammalian cells revealed increased intracellular cAMP level when exposed to mammalian and fish gonadotropins; the most potent hormone was salmon GTH II. These results indicate that the cloned cDNA encodes a functional amago salmon GTH receptor protein.
Assuntos
Oncorhynchus/genética , Ovário/química , Receptores da Gonadotropina/genética , Testículo/química , Sequência de Aminoácidos , Animais , Sequência de Bases , Células COS , Clonagem Molecular , AMP Cíclico/metabolismo , DNA Complementar/genética , Evolução Molecular , Feminino , Masculino , Dados de Sequência Molecular , Receptores da Gonadotropina/classificação , Receptores da Gonadotropina/isolamento & purificação , Receptores do LH/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , TransfecçãoRESUMO
The receptors for the gonadotropins differ from the other G protein-coupled receptors by having a large extracellular hormone-binding domain, encoded by nine or ten exons. Alternative splicing of the large pre-mRNA of approximately 100 kb can result in mRNA species that encode truncated receptor proteins. In this review we discuss the regulation of gonadotropin receptor mRNA expression and the possible roles of alternative splicing in gonadotropin receptor function.
