ABSTRACT
Mutations in the mouse coat color gene agouti were recognized to cause an adult-onset obesity by 1905, and the agouti gene was finally cloned and characterized nearly a century later. Agouti is transiently expressed in neonatal skin, where it controls the relative amount and distribution of melanin produced by the hair follicle melanocytes. A number of dominant mutations at the agouti locus result in ectopic agouti expression in virtually all tissues throughout the life of the mouse. Dominant agouti mutants exhibit maturity-onset obesity. Increases in body weight are first observed around 4 weeks of age, and peak between 8 and 17 months. Agouti protein contains a 22-amino acid signal sequence, a highly basic central region in which 16 of the 29 amino acids are lysine or arginine residues, a poly-proline-rich region that follows the basic region, and a cysteine-rich carboxyl-terminal region.
