title: Evolution of keratin genes: different protein domains evolve by different pathways.
abstract: Intermediate filaments are composed of a family of proteins that evolved from a common ancestor. The proteins consist of three domains: a central, alpha-helical domain similar in all intermediate filaments, bracketed by two domains that are variable in length and structure. Within the intermediate-filament family, several subfamilies have been recognized by immunologic and nucleic acid hybridization techniques. In this paper we present the sequence of the genomic DNA coding for a 65-kilodalton human keratin and compare it with the sequences of other intermediate-filament proteins. While the central, alpha-helical domains of these proteins show homologies that indicate a common ancestor, the sequences of the variable terminal domains indicate that the variable domains evolved through a series of tandem duplications and possibly by gene-conversion mechanisms.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002417:Cattle; D006224:Cricetinae; D005796:Genes; D006801:Humans; D007382:Intermediate Filaments / Q000032:analysis; D007633:Keratins / Q000235:genetics*; D051379:Mice; D011487:Protein Conformation; D012756:Sheep; D013045:Species Specificity
chemical_list: D007633:Keratins