Chromosomal structure of the human TYRP1 and TYRP2 loci and comparison of the tyrosinase-related protein gene family.

The structures of the human tyrosinase-related protein genes TYRP1 and TYRP2 have been determined and compared with that of the tyrosinase gene (TYR). The TYRP1 protein is encoded in 7 exons spread over 24 kb of genomic DNA. Characterization of a 55-kb contig encompassing the human TYRP2 locus reveals that the protein coding region is divided into 8 exons. All three members of the TYRP gene family share a common C-terminal membrane spanning exon. Examination of the position of other intron junctions suggests that TYRP1 was derived from a TYR duplication and then was itself duplicated to give rise to the TYRP2 gene. The evidence also suggests that at least some of the introns within the TYR, TYRP1, and TYRP2 coding regions were gained after duplication and that intron slippage is unlikely to have occurred.