| Research Abstract |
In this study, we succeeded to isolate two cDNA clones of maturation-inducing steroid hormone (17alpha,20beta-dihyciroxy-4-pregnen-3-one) receptors, from medaka (Olyzias la tipes) ovary. These two cDNAs are classified as alpha (OlGPCPR-alpha) and gamma (OlGPCPR-gamma) subtypes. The cDNAs of OlGPCPR-alpha and OlGPCPR-gamma are 2983 by and 1566 by in lengths, respectively, and both cDNAs have an open reading frame encoding a protein of 352 amino acids. Sequence analysis revealed that both belonged to the G-protein-coupled receptor family with the typical 7 transmembrane domains. The amino acid sequence of OlGPCPR-alpha has 86.9% identity with the seatrout sequence and 48.4% with OlGPVPR-gamma. Northern blot analysis shows that OlGPCPR-alpha is expressed in brain, heart, kidney, ovary and testis, in contrast, OlGPCPR-gamma is expressed in ovary and testis. Polyclonal antibodies were generated in rabbits for Western blotting analysis of the receptor proteins. We also isolated a cDNA clone of the medaka homologue of membrane progestin receptor with a single transmembrane domain. The cDNA has an ORF encoding a protein of 198 AA and has 52 % identity with the sequence of human DG6.
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