Genes for intermediate filament proteins and the draft sequence of the human genome

The study screened the draft sequence of the human genome for genes encoding intermediate filament (IF) proteins, focusing on keratins. It identified 65 IF genes, making it one of the 100 largest gene families in humans. Seven novel type II keratins were found, likely expressed in hair follicles/epidermal appendages. All functional keratin genes were mapped to known clusters on chromosomes 12 and 17, while other IF genes were not clustered. Of 208 keratin-related sequences, only 49 were true keratin genes, with most being inactive fragments or pseudogenes, particularly related to keratins 8 and 18. The study highlighted the uneven distribution of pseudogenes in the IF family and suggested extending the existing keratin nomenclature to include novel keratins.