Cloning and tissue distribution of novel GnRH receptors in the European sea bass, Dicentrarchus labrax.

MONCAUT, N.P.; SOMOZA, G.M.; CANÁRIO, A.V.M.

Castellón. España

Congreso; 5th International Symposium on Fish Endocrinology; 2004

ESCE

CLONING AND TISSUE DISTRIBUTION OF NOVEL GnRH RECEPTORS IN THE EUROPEAN SEA BASS, Dicentrarchus labrax N. Moncaut1, G. Somoza2 & A.Canario1. 1Comparative and Molecular Endocrinology Lab, CCMAR, University of Algarve, Campus de Gambelas 8000-117 Faro, Portugal. nmoncaut@ualg.pt 2 Laboratorio de Ictiofisiologia y Acuicultura (IIB-INTECH) Camino de Circunvalacion Laguna Km. 6 (B7130IWA). Pcia de Buenos Aires. Argentina. The events leading to GnRH-stimulated gonadotropin synthesis and release from the anterior pituitary is dependent on the presence of gonadotropin releasing hormone receptors (GnRHRs) and the existence of multiple GnRH forms in only one species suggests that more than one GnRHR may exist in one organism. Using an in silico analysis, five putative GnRHRs were found in the Fugu rubripes genome database. Phylogenetic analysis of these and available sequences from other teleosts resulted into two main lineages of piscine GnRHRs which could be subdivided in a total of five clades. Five partial cDNA fragments of GnRHRs were cloned by PCR using primers designed on the basis of each clade in the European sea bass: GnRHR-1A (Gonzalez-Martinez et al., 2004), GnRHR-1B (AJ606686), GnRHR-1C (AJ606684), GnRHR-2A (AJ606683) and GnRHR-2B (AJ606685). Screening of a brain and pituitary cDNA library yielded up to now four full length clones. Semi-quantitative RT-PCR analysis show important differences in the level of expression and wide tissue distribution of these receptors. Further work will analyse ligand specificity and possible redundancy of the GnRHR subtypes. Acknowledgment: N.M. funded by Fundação para a Ciência e Tecnologia, Portugal (full description BD 6083 / 2002) and CONICET (Argentina). González–Martinez D., et al. 2004. Biol Reprod 2004; 10.1095/biolreprod.103.022624