MOLECULAR-STRUCTURE AND CHROMOSOMAL MAPPING OF THE HUMAN HOMOLOG OF THE AGOUTI GENE

The agouti (a) locus in mouse chromosome 2 normally regulates coal col or pigmentation. The mouse agouti gene was recently cloned and shown t o encode a distinctive 131-amino acid protein with a consensus signal peptide. Here we describe the cloning of the human homolog of the mous e agouti gene using an interspecies DNA-hybridization approach. Sequen ce analysis revealed that the coding region of the human agouti gene i s 85% identical to the mouse gene and has the potential to encode a pr otein of 132 amino acids with a consensus signal peptide. Chromosomal assignment using somatic-cell-hybrid mapping panels and fluorescence i n situ hybridization demonstrated that the human agouti gene maps to c hromosome band 20q11.2. This result revealed that the human agouti gen e is closely linked to several traits, including a locus called MODY ( for maturity onset diabetes of the young) and another region that is a ssociated with the development of myeloid leukemia. initial expression studies with RNA from several adult human tissues showed that the hum an agouti gene is expressed in adipose tissue and testis.