NUCCI, NV; REED, KL; LEE, KJ; BOURN, CA; TROSKIE, BE; SOWER, SA*: Molecular Cloning of the GnRH Receptor cDNA in the Sea Lamprey, Petromyzon Marinus

Gonadotropin-releasing hormone (GnRH) is the hypothalamic peptide central in the control of reproduction in vertebrates. Two molecular forms of GnRH, lamprey GnRH-I and lamprey GnRH-III, have been sequenced in the sea lamprey and both have been shown to act as neurohormones regulating reproduction. Previous studies have shown two distinct GnRH binding sites in the pituitary of the sea lamprey. GnRH?s action is modulated through a 7-transmembrane G-protein coupled receptor. In the present study, the cDNA of the GnRH receptor has been cloned. Complimentary DNA was constructed from lamprey brain total RNA and a 123 base partial sequence of the receptor was isolated by RT-PCR using the primers, JH5S and JH6A. From this partial sequence, gene specific primers were designed and used for 5? and 3? RACE with the Marathon cDNA Amplification Kit (CLONTECH). 5? and 3? clones were obtained and sequenced to yield the primary sequence for the lamprey brain GnRH receptor. This receptor has significant identity to several other GnRH receptor cDNAs including 61.2% with the aquatic caecilian Typhlonectes natans, 60.7% and 59.8% with the bullfrog Rana catesbeiana receptors 1 and 3, respectively, and 59% with the striped sea bass Morone saxatilis. (Supported by National Science Foundation to SAS).