CLONING AND SEQUENCE-ANALYSIS OF A NEUROPEPTIDE-Y PEPTIDE YY RECEPTORY1 CDNA FROM XENOPUS-LAEVIS

Neuropeptide Y (NPY) and peptide YY (PYY) are structurally related pep tides that share at least two distinct receptors denoted Y1 and Y2. Th e Y1 receptor has previously been cloned in man, rat and mouse. We des cribe here the cloning and sequence of a Xenopus laevis Y1 receptor th at shares 81% amino acid sequence identity with the human receptor in the region spanning transmembrane (TM) regions I to VII. The extracell ular amino-terminal part, TM IV and the second extracellular loop cont ain several replacements suggesting that these portions have no or lim ited direct interactions with the peptide ligands. The intracellular r egions including the carboxy-terminal tail are nearly identical betwee n Xenopus and mammals, suggesting strong structural constraints on the portions that may interact with G proteins.