GENOMIC ORGANIZATION AND FISH MAPPING OF HUMAN PMEL-17, THE PUTATIVE SILVER LOCUS

The Pmel 17 gene is expressed preferentially in pigment cells. It has been mapped to human chromosome 12 pter-q21 and mouse chromosome 10, n ear the silver locus. The Pmel 17 gene contains an insertional mutatio n at its carboxyl terminus in the silver mouse, suggesting that the si lver locus might correspond to the gene. In the current studies, we ha ve isolated and characterized human Pmel 17 genomic clones and employe d FISH mapping for a precise localization of this gene in the human ch romosome. The FISH mapping placed the Pmel 17 gene at human chromosome 12 q12-q13. The human gene consists of nine exons and eight introns, and the entire coding region of the gene spans approximately 7.9 kb of the human chromosome 12. The putative functional domains, such as the signal sequence, histidine-rich, 26-amino acid repeats, cysteine-rich , transmembrane and cytoplasmic domains, were encoded by separate exon s. Cis-transcription elements such as a TATA, a CAT and other potentia l elements for pigment cell-specific gene expression were found within 1100 base pairs of the 5' flanking region.