Meeting Abstract

P1.140  Sunday, Jan. 4  Isolation and expression patterns of cDNAs for three vasotocin receptors and an isotocin receptor from a teleost, the Amargosa pupfish LEMA, S.C.; Univ. of North Carolina, Wilmington lemas@uncw.edu

Arginine vasopressin regulates hydromineral balance, vasoconstriction and sociosexual behaviors in mammals, and the related hormone arginine vasotocin has been implicated to play similar roles in birds, amphibians and teleost fish. While three distinct receptors for vasopressin (V1a, V1b and V2) have been identified in mammals, only a single receptor has been found in teleosts. Here, cDNAs for vasotocin receptors were isolated and sequenced from the Amargosa pupfish (Cyprinodon nevadensis amargosae) – a species studied previously for vasotocin’s role in regulating aggression. Using degenerate primer PCR and 5′- and 3′-rapid amplification of cDNA ends (RACE), two full-length cDNAs encoding deduced sequences of 497 and 385 amino acid residues, and a third cDNA encoding a 325 residue partial open reading frame, were identified. The 497 residue cDNA exhibited highest identity (49.0-57.4%) to V2-type vasopressin/vasotocin receptors of mammals and amphibians, and lower identity to V1a (37.8-39.6%) and V1b (41.1-41.9%) receptors. The cDNA encoding 385 amino acids had greater identity to V1a-type receptors from mammals and amphibians (58.6-62.6%) than to V1b (51.5-53.5%) and V2 (38.6-45.0%) receptors. Similarly, the partial cDNA for 325 residues also showed greater identity to V1a receptors from mammals (56.7-58.5%) and amphibians (59.5-61.5%), than to either mammalian V1b (54.7-55.4%) or V2 (40.9-42.1%) receptors. A fourth full-length cDNA encoding an isotocin receptor of 395 amino acids has also been identified from this pupfish. Future characterization of the function and expressional regulation of these receptors will provide new insights into the evolutionary and functional diversity of the vasotocin/vasopressin and isotocin/mesotocin/oxytocin receptor families in vertebrates.