053 Two Novel Human Keratin-Associated Proteins Expressed in the Cortical Layer of the Hair Follicle Have been Termed hKAP1.6 and hKAP1.7

Y. Shimomura1, N. Aoki1, L. Langbein2, M. A. Rogers3, J. Schweizer3, and M. Ito1. Department of Dermatology, Niigata University School of Medicine, Niigata, Japan1; The Divisions of Cell Biology2 and Biochemistry3 of Tissue Specific Regulation, German Cancer Reserch Center, Heidelberg, Germany

Hair follicle differentiation involves the expression of hair keratin-associated proteins (KAPs) as well as both epithelial or cytokeratins and hair keratins. In the present study, we have isolated two cDNAs coding for new members of human KAP1 family from human genome and hair follicle mRNA during the analysis of hKAP1.1 gene in the patient with fragile hairs. PCR and RT-PCR results using hKAP1.1 specific primers showed the presence of a novel hKAP1 member. To thus isolate the 3` end of its cDNA, we developed a twofold strategy, 3` RACE and screening of a human scalp cDNA library with the hKAP1.1 probe, and isolated two cDNAs. The predicted amino acid sequences derived from two clones, revealed a homology with a number of keratin-associated proteins, indicating that these proteins belong to new members of human KAP1 family. RNA in situ hybridization study of human anagen hair follicles demonstrated the predominant expression of their transcripts in the cortical layer throughout the keratogenous zone. Taken together the multi-alignment of the members of KAP1 family analyzed, we have termed two novel keratinassociated proteins hKAP1.6 and hKAP1.7.