Defining the Complex Epithelia That Comprise the Canine Claw With Molecular Markers of Differentiation

October 2009 in “ Veterinary Dermatology ”

Paul E. Bowden, Hayley Henderson, J. D. REILLY

TLDR Canine claws have complex structures with different keratin types, similar to hair and nails.

The study investigated the complex epithelial structures of canine claws, which resemble mammalian hair fibers and human nail plates. Researchers examined keratin expression in the claws of German shepherd dogs, identifying distinct regions and cell lineages undergoing hard or soft keratinization. The claw plate expressed hair-specific keratins, while the soft keratinizing sole epithelium expressed different keratins, including K5, K6, K14, K16, and K17. Two slippage zones were identified, with specific keratin expressions, indicating a complex mechanism of cellular differentiation in canine claws.

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research Keratin K6irs is specific to the inner root sheath of hair follicles in mice and humans

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research The Catalog of Human Hair Keratins

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research Keratin 17 Expression in the Hard Epithelial Context of the Hair and Nail, and its Relevance for the Pachyonychia Congenita Phenotype

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research Keratin expression in the normal nail unit: markers of regional differentiation

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research The Catalog of Human Hair Keratins

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research A Novel Human Type II Cytokeratin, K6hf, Specifically Expressed in the Companion Layer of the Hair Follicle

139 citations , December 1998 in “The journal of investigative dermatology/Journal of investigative dermatology”

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research Characterization of a 190-Kilobase Pair Domain of Human Type I Hair Keratin Genes

74 citations , October 1998 in “Journal of biological chemistry/The Journal of biological chemistry”

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research Expression of keratin K14 in the epidermis and hair follicle: insights into complex programs of differentiation.

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research A group of type I keratin genes on human chromosome 17: characterization and expression.

141 citations , February 1988 in “Molecular and Cellular Biology”

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research Chapter 3 Expression and Modification of Keratins During Terminal Differentiation of Mammalian Epidermis

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research Acidic and Basic Hair/Nail (Hard) Keratins: Their Colocalization in Upper Cortical and Cuticle Cells of the Human Hair Follicle and Their Relationship to Soft Keratins

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Defining the Complex Epithelia That Comprise the Canine Claw With Molecular Markers of Differentiation

Research cited in this study

research K25 (K25irs1), K26 (K25irs2), K27 (K25irs3), and K28 (K25irs4) Represent the Type I Inner Root Sheath Keratins of the Human Hair Follicle

research Expression of hair keratins in the adult nail unit: an immunohistochemical analysis of the onychogenesis in the proximal nail fold, matrix and nail bed

research K6irs1, K6irs2, K6irs3, and K6irs4 Represent the Inner-Root-Sheath-Specific Type II Epithelial Keratins of the Human Hair Follicle1

research Keratin K6irs is specific to the inner root sheath of hair follicles in mice and humans

research The Catalog of Human Hair Keratins

research Keratin 17 Expression in the Hard Epithelial Context of the Hair and Nail, and its Relevance for the Pachyonychia Congenita Phenotype

research Keratin expression in the normal nail unit: markers of regional differentiation

research The Catalog of Human Hair Keratins

research A Novel Human Type II Cytokeratin, K6hf, Specifically Expressed in the Companion Layer of the Hair Follicle

research Characterization of a 190-Kilobase Pair Domain of Human Type I Hair Keratin Genes

research Characterization and Chromosomal Localization of Human Hair-Specific Keratin Genes and Comparative Expression During the Hair Growth Cycle

research Mutation of a type II keratin gene (K6a) in pachyonychia congenita

research Hair Follicle Companion Layer: Reacquainting an Old Friend

research Sequence and Expression of Human Hair Keratin Genes

research The extraction and characterization of human nail keratin

research Expression of keratin K14 in the epidermis and hair follicle: insights into complex programs of differentiation.

research A group of type I keratin genes on human chromosome 17: characterization and expression.

research Keratins of the human hair follicle: “Hyperproliferative” keratins consistently expressed in outer root sheath cells in vivo and in vitro

research Chapter 3 Expression and Modification of Keratins During Terminal Differentiation of Mammalian Epidermis

research Acidic and Basic Hair/Nail (Hard) Keratins: Their Colocalization in Upper Cortical and Cuticle Cells of the Human Hair Follicle and Their Relationship to Soft Keratins