GENOMIC ORGANIZATION OF A RECEPTOR FROM SEA-ANEMONES, STRUCTURALLY AND EVOLUTIONARILY RELATED TO GLYCOPROTEIN HORMONE RECEPTORS FROM MAMMALS

Cnidarians (e.g., sea anemones and corals) are the lowest animal group having a nervous system. Previously, we cloned a receptor from sea an emones that showed a strong structural similarity to the glycoprotein hormone (TSH, FSH, LH/CG) receptors from mammals. Here, we determine t he genomic organization of this sea anemone receptor. The receptor gen e contains eight introns that are all localized within a region coding for the large extracellular N terminus. These introns occur at the sa me positions and have the same intron phasing as eight introns in the genes coding for the mammalian glycoprotein hormone receptors, indicat ing that the cnidarian and mammalian receptor genes are evolutionarily related. As with the mammalian receptor genes, the sea anemone recept or gene does not contain introns in the region coding for the transmem brane and intracellular domains. Southern blot analyses show that the cnidarian receptor is coded for by a single gene. (C) 1998 Academic Pr ess.