CLONING AND STRUCTURAL CHARACTERIZATION OF HUMAN HAIR SULFUR-RICH KERATIN GENES

This is a pioneer study of the isolation and cloning of two sulfur-ric h hair keratin genes within a 15-kbp fragment found in the human DNA g enomic library. The primary structure of gene coding regions and their 5'- and 3'-flanking sequences were determined. The TATA boxes, initia ting codons, and an 18-nucleotide sequence specific for keratin genes, previously described in sheep keratin genes and designated as ''matri x-specific,'' were revealed at the 5'-flanking region. The sulfur-rich keratin amino acid sequence was deduced from the nucleotide sequence, thus enabling us for the first time to obtain a picture of the primar y and, consequently, secondary and tertiary structures of these previo usly unknown proteins. The hypothetical functional role of these struc tural elements and the problems of their modifications in mammalian ev olution are discussed.