Mammalian Keratin-Associated Proteins (KRTAPs) Subgenomes: Disentangling Hair Diversity and Adaptation to Terrestrial and Aquatic Environments

September 2014 in “ BMC genomics ”

Imran Khan, Emanuel Maldonado, Vı́tor Vasconcelos, Stephen J. O’Brien, Warren E. Johnson, Agostinho Antunes

keratin-associated proteins KRTAPs cysteine glycine-tyrosine gene conversion pseudogenization hair diversity hair adaptation keratin proteins hair proteins

Studysummary This research found that variations in the KRTAP gene family are likely responsible for the diverse hair phenotypes seen among mammals, influenced by gene repertoire differences, expression, and evolutionary factors.

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The study on mammalian keratin-associated proteins (KRTAPs) examined the genetic basis of hair diversity and adaptation in 22 mammalian species, revealing 30 subfamilies with distinct evolutionary patterns. High cysteine KRTAPs showed strong concerted evolution and high gene conversion rates, while high glycine-tyrosine KRTAPs exhibited positive selection and lower gene conversion. Species with more complex hair had more KRTAP genes, with the sloth having the most (175 genes) and the dolphin the fewest (35 genes) with a high pseudogenization rate. The findings suggested that KRTAP gene variations and expression patterns contribute to unique hair characteristics and environmental adaptations in mammals.

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research Identification and Sequence Analysis of the Keratin-Associated Protein 24-1 (KAP24-1) Gene Homologue in Sheep

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research Characterization of the Human Hair Keratin-Associated Protein 2 (KRTAP2) Gene Family

52 citations , April 2012 in “Journal of Investigative Dermatology”

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research Ultrastructural Localization of Hair Keratin Homologs in the Claw of the Lizard Anolis Carolinensis

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research Evolution of Hard Proteins in the Sauropsid Integument in Relation to the Cornification of Skin Derivatives in Amniotes

86 citations , April 2009 in “Journal of anatomy”

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research Expression Patterns of Keratin Intermediate Filament and Keratin Associated Protein Genes in Wool Follicles

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research The Hair Follicle as a Dynamic Mini-Organ

759 citations , February 2009 in “Current Biology”

This review summarizes fundamental concepts and recent advancements in hair follicle biology, including insights from mouse models into broader molecular and cellular processes relevant to regeneration and development.

research Identification of Reptilian Genes Encoding Hair Keratin-Like Proteins Suggests a New Scenario for the Evolutionary Origin of Hair

115 citations , November 2008 in “Proceedings of the National Academy of Sciences”

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research Molecular Evolution of the Keratin Associated Protein Gene Family in Mammals: Role in the Evolution of Mammalian Hair

119 citations , August 2008 in “BMC Evolutionary Biology”

This study found that while the KRTAP gene family is unique to mammals, humans have a similar number of these hair gene types as other primates despite having less body hair.

research Characterization and Expression Analysis of the Hair Keratin Associated Protein KAP26.1

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research Embryonic Keratinization in Vertebrates in Relation to Land Colonization

44 citations , May 2008 in “Acta Zoologica”

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research Characterization of Human KAP24.1, A Cuticular Hair Keratin-Associated Protein with Unusual Amino Acid Composition and Repeat Structure

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research Human Hair Keratin-Associated Proteins: Sequence Regularities and Structural Implications

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research Proteome Analysis of Human Hair Shaft

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research Structural and Immunocytochemical Characterization of Keratinization in Vertebrate Epidermis and Epidermal Derivatives

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research Human Hair Keratin-Associated Proteins

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research Terrestrial Vertebrates Have Two Keratin Gene Clusters; Striking Differences in Teleost Fish

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research Size Polymorphisms in the Human Ultrahigh Sulfur Hair Keratin-Associated Protein 4, KAP4, Gene Family

27 citations , June 2005 in “The journal of investigative dermatology/Journal of investigative dermatology”

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research Human KAP Genes: Only Half of It? Extensive Size Polymorphisms in Hair Keratin-Associated Protein Genes

53 citations , June 2005 in “The journal of investigative dermatology/Journal of investigative dermatology”

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research Characterization of New Members of the Human Type II Keratin Gene Family and a General Evaluation of the Keratin Gene Domain on Chromosome 12q13.13

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research The Human Type I Keratin Gene Family: Characterization of New Hair Follicle Specific Members and Evaluation of the Chromosome 17q21.2 Gene Domain

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research Krtap16: Characterization of a New Hair Keratin-Associated Protein Gene Complex on Mouse Chromosome 16 and Evidence for Regulation by Hoxc13

47 citations , September 2004 in “Journal of Biological Chemistry”

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research Fine Structure of Marsupial Hairs, with Emphasis on Trichohyalin and the Structure of the Inner Root Sheath

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research Identification of Two Novel Clusters of Ultrahigh-Sulfur Keratin-Associated Protein Genes on Human Chromosome 11

27 citations , April 2004 in “Biochemical and Biophysical Research Communications”

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research Comparative Genomics of the Keratin-Associated Protein Gene Clusters in Human, Chimpanzee, and Baboon

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research A Cluster of 21 Keratin-Associated Protein Genes Within Introns of Another Gene on Human Chromosome 21q22.3

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research Hair Follicle Differentiation And Regulation

199 citations , January 2004 in “The International Journal of Developmental Biology”

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Hair Keratin Associated Proteins: Characterization of a Second High Sulfur KAP Gene Domain on Human Chromosome 21 in Fond Memory of Dr. Peter Steinert

research Hair Keratin Associated Proteins: Characterization of a Second High Sulfur KAP Gene Domain on Human Chromosome 21 in Fond Memory of Dr. Peter Steinert

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research Molecular Biology of Hair Morphogenesis: Development and Cycling

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research Characterization of a First Domain of Human High Glycine-Tyrosine and High Sulfur Keratin-Associated Protein Genes on Chromosome 21q22.1

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research Molecular Mechanisms Regulating Hair Follicle Development

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research HKAP1.6 And HKAP1.7, Two Novel Human High Sulfur Keratin-Associated Proteins Are Expressed In The Hair Follicle Cortex

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research Characterization of a Cluster of Human High/Ultrahigh Sulfur Keratin-Associated Protein Genes Embedded in the Type I Keratin Gene Domain on Chromosome 17q12-21

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research Characterization of a 300 Kbp Region of Human DNA Containing the Type II Hair Keratin Gene Domain

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

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research Characterization of a Gene Encoding a Cysteine-Rich Keratin Associated Protein Synthesized Late in Rabbit Hair Follicle Differentiation

26 citations , March 1995 in “Differentiation”

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research Differential Expression of Genes Encoding a Cysteine-Rich Keratin Family in the Hair Cuticle

35 citations , September 1994 in “Journal of Investigative Dermatology”

research Regulation of Keratin Gene Expression in Hair Follicle Differentiation

98 citations , December 1991 in “Annals of the New York Academy of Sciences”

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