Alternative titles; symbols
HGNC Approved Gene Symbol: KRT15
Cytogenetic location: 17q21.2 Genomic coordinates (GRCh38): 17:41,513,745-41,518,890 (from NCBI)
Keratins are a family of structurally related proteins that form intermediate filaments in epithelial cells. Keratins can be divided into 2 subfamilies: acidic (type I), to which keratin-15 (KRT15) belongs, and basic (type II). A comparison of the amino acid and nucleotide sequences corresponding to different keratin polypeptides shows a constant principle of organization, namely, a conserved central rod of coiled-coil alpha-helical arrangement of 300 to 330 amino acids flanked by head and tail regions of highly variable sizes. Sequence homologies are restricted to the alpha-helical core portion. Members of the acidic subfamily display little, if any, amino acid homology to polypeptides of the basic one. Although in vitro any of the 10 to 15 acidic polypeptides is able to associate with any of the basic ones, the composition of the keratin pairs found in vivo is highly specific. For example, the basal cells of human epidermis express 2 keratin subunits, acidic keratin 14 (KRT14; 148066) and basic keratin 5 (KRT5; 148040), whereas suprabasal cells committed to terminal differentiation express acidic keratin 10 (KRT10; 148080) and basic keratin 1 (KRT1; 139350).
Hanukoglu and Fuchs (1982) sequenced a cloned cDNA complementary to the mRNA for the 50-kilodalton human epidermal keratin.
Marchuk et al. (1985) reported the complete nucleotide sequence for a gene encoding the 50-kD keratin expressed in abundance in human epidermal cells. (Keratin represents almost 30% of the protein synthesized in basal epidermal cells.) The gene appears to have a single transcriptional initiation site and a single polyadenylation signal. Upstream, 3 regulatory sequences sharing homology with viral and immunoglobulin enhancer elements were found.
Using a cDNA probe in the analysis of a panel of human-hamster cell hybrids, Romano et al. (1987) mapped the gene for what they termed cytokeratin 13 to chromosome 17; later, Romano et al. (1988) revised the identification of the gene they studied and referred to it as cytokeratin 15.
Barletta et al. (1989, 1990) showed by in situ hybridization that cytokeratin 15 is localized to human chromosome 17q21-q23.
Romano et al. (1991) demonstrated that the KRT10, KRT13 (148065), and KRT15 genes are located in the same large pulsed field gel electrophoresis fragment. A correlation of assignments of the 3 genes makes 17q21-q22 the likely location of the cluster.
Types I and II (Fuchs et al., 1981) represent the 2 distinct sequence classes of the 20 polypeptides that comprise 8 nm cytoplasmic filaments in most, if not all, epithelial cells. Although the sequences of the 2 classes differ, their secondary structures are very similar. At least 1 member of each of the 2 keratin classes is expressed in all tissues, suggesting the importance of the 2 types of sequences in filament assembly.
RayChaudhury et al. (1986) rejected the suggestion that different keratin mRNAs may arise by differential processing of a small number of heterogeneous nuclear RNA transcripts. They also isolated 3 separate type I keratin genes and showed that they are physically tightly linked. They appear to be separate from the previously sequenced type I keratin gene referred to as K14 (Marchuk et al., 1985).
Blumenberg and Savtchenko (1986) proposed that the human genome contains at least 20 genes for keratin proteins. In epithelial intermediate filaments, keratins from both families appear to be coordinately expressed.
Savtchenko et al. (1990) demonstrated physical linkage of 3 groups of acidic keratin genes.
Barletta, C., Batticane, N., Ragusa, R. M., Leube, R. E., Franke, W. W., Peschle, C., Romano, V. Sub-chromosomal localization of human cytokeratin 4, 15, and 19 genes. (Abstract) Cytogenet. Cell Genet. 51: 958 only, 1989.
Barletta, C., Batticane, N., Ragusa, R. M., Leube, R., Peschle, C., Romano, V. Subchromosomal localization of two human cytokeratin genes (KRT4 and KRT15) by in situ hybridization. Cytogenet. Cell Genet. 54: 148-150, 1990. [PubMed: 1702379] [Full Text: https://doi.org/10.1159/000132979]
Blumenberg, M., Savtchenko, E. S. Linkage of human keratin genes. Cytogenet. Cell Genet. 42: 65-71, 1986. Note: Erratum: Cytogenet. Cell Genet. 61: 160 only, 1992. [PubMed: 2424675] [Full Text: https://doi.org/10.1159/000132253]
Fuchs, E., Coppock, S., Green, H., Cleveland, D. Two distinct classes of keratin genes and their evolutionary significance. Cell 27: 75-84, 1981. [PubMed: 6173133] [Full Text: https://doi.org/10.1016/0092-8674(81)90362-7]
Fuchs, E., Green, H. Changes in keratin gene expression during terminal differentiation of the keratinocyte. Cell 19: 1033-1042, 1980. [PubMed: 6155214] [Full Text: https://doi.org/10.1016/0092-8674(80)90094-x]
Hanukoglu, I., Fuchs, E. The cDNA sequence of a human epidermal keratin: divergence of sequence but conservation of structure among intermediate filament proteins. Cell 31: 243-252, 1982. [PubMed: 6186381] [Full Text: https://doi.org/10.1016/0092-8674(82)90424-x]
Lee, L. D., Baden, H. P. Organisation of the polypeptide chains in mammalian keratin. Nature 264: 377-379, 1976. [PubMed: 1004564] [Full Text: https://doi.org/10.1038/264377a0]
Marchuk, D., McCrohon, S., Fuchs, E. Complete sequence of a gene encoding a human type I keratin: sequences homologous to enhancer elements in the regulatory region of the gene. Proc. Nat. Acad. Sci. 82: 1609-1613, 1985. [PubMed: 2580298] [Full Text: https://doi.org/10.1073/pnas.82.6.1609]
RayChaudhury, A., Marchuk, D., Lindhurst, M., Fuchs, E. Three tightly linked genes encoding human type I keratins: conservation of sequence in the 5-prime-untranslated leader and 5-prime-upstream regions of coexpressed keratin genes. Molec. Cell. Biol. 6: 539-548, 1986. [PubMed: 2431270] [Full Text: https://doi.org/10.1128/mcb.6.2.539-548.1986]
Romano, V., Bosco, P., Costa, G., Leube, R., Franke, W. W., Rocchi, M., Romeo, G. Chromosomal assignment of cytokeratin genes. (Abstract) Cytogenet. Cell Genet. 46: 683 only, 1987.
Romano, V., Bosco, P., Raimondi, E., Feo, S., Leube, R., Franke, W., Ceratto, N. Chromosomal mapping and physical linkage analysis of human acidic cytokeratin genes. (Abstract) Cytogenet. Cell Genet. 58: 2009-2010, 1991.
Romano, V., Bosco, P., Rocchi, M., Costa, G., Leube, R. E., Franke, W. W., Romeo, G. Chromosomal assignments of human type I and type II cytokeratin genes to different chromosomes. Cytogenet. Cell Genet. 48: 148-151, 1988. [PubMed: 2466616] [Full Text: https://doi.org/10.1159/000132612]
Savtchenko, E. S., Tomic, M., Ivker, R., Blumenberg, M. Three parallel linkage groups of human acidic keratin genes. Genomics 7: 394-407, 1990. [PubMed: 1694815] [Full Text: https://doi.org/10.1016/0888-7543(90)90174-s]