Genomic organization and promoter characterization of two human UHS keratin genes

TTD is a rare human genetic disease caused by mutations in XPB and XPD, two subunits of the transcription/repair factor TFIIH, and whose outstanding c linical characteristic is a lack of most human UHS proteins resulting in su lfur-deficient brittle hair. In an attempt to understand this transcription defect, we report here the genomic cloning of two highly related UHS kerat in genes specifically expressed in follicular and epidermal cells. In addit ion to a high degree of nucleotide homology (87%), both genes also have a s imilar 90-nt promoter sequence. In-vivo and in-vitro studies allowed us to specify the position of the start sites, the TATA-boxes and some regulatory regions. Results indicate that both genes present common features in the r egulation of their transcription and suggest that control of their expressi on might be affected by mutations in TFIIH subunits. (C) 1999 Elsevier Scie nce B.V. All rights reserved.