Molecular analysis of a new splice variant of the human melanocortin-1 receptor

The primary hormonal regulator of pigmentation is melanocyte stimulating ho rmone derived from proopiomelanocortin by proteolytic processing. The melan ocortin-1 receptor sen es a key role in the regulation of pigmentation, We describe the identification of the first intron within a melanocortin recep tor. A new melanocortin-1 receptor isoform, generated by alternative mRNA s plicing, encodes an additional 65 amino acids at the predicted intracellula r, C-terminal tail of the melanocortin-1 receptor, When expressed in hetero logous cells, the new spliced form of the melanocortin-1 receptor (melanoco rtin-1 receptor B) appears pharmacologically similar to the non-spliced mel anocortin-1 receptor, Melanocortin-1 receptor B is expressed in testis, fet al heart and melanomas, (C) 1999 Federation of European Biochemical Societi es.