FREAMAT, M.*; SOWER, S.A.; University of New Hampshire, Durham; University of New Hampshire, Durham: Progress in Molecular Cloning of a cDNA Encoding the Gonadotropin Hormone Receptor in the Sea Lamprey.

As a member of the class Agnatha, sea lampreys, Petromyzon marinus, represent one of the two oldest lineages of vertebrates. Given their phylogenetic position, lampreys are important in evolutionary studies and for understanding the molecular evolution of endocrine systems. Considerable research has been performed to establish that, similar to teleosts and later evolved vertebrates, the sea lamprey has a functional hypothalamus-pituitary-gonadal axis that controls reproduction. Despite numerous collaborative efforts to isolate the gonadotropin(s) (GTH) in lampreys, involving various protein extraction and chromatography methods and extensive molecular studies, no protein with identity to other known GTH molecules has been isolated, however there is overwhelming biological and immunological evidence for a GTH-like molecule in lampreys. Therefore, the goal of this study is to perform �reverse endocrinology� and to isolate and sequence the cDNA of gonadotropin receptor(s). This paper reports the progress obtained in the molecular cloning of the gonadotropin hormone receptor (GTH-R) in sea lamprey. Reverse transcriptase PCR based methodology has been used. Nondegenerate primer pairs targeted towards conserved regions in homologous sequences led to isolation of a related molecule. In addition, we have attempted an iteratively nested cloning strategy using a degenerate primer system derived from the PRINTS database signature for glycoprotein hormone receptors. The identification of GTH-R in agnathans will both further the study of reproduction in these fish and enhance understanding of the molecular evolution of pituitary hormones. Supported by NSF to SAS and Intl NSF-JSPS to SAS and Hiroshi Kawauchi.