Terrestrial vertebrates have two keratin gene clusters; striking differences in teleost fish

Zimek, Alexander; Weber, Klaus

doi:10.1016/j.ejcb.2005.01.007

Cited by 44 publications

(41 citation statements)

References 29 publications

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“…This demonstrates that the expression of Anolis hair keratin-like genes is not strictly confined to claws and leaves open the possibility that the primordial hard keratins of ancestral sauropsids were also present in scales. The identification of hard keratin genes in reptiles and in birds strongly argues against the concept that hair keratins were an evolutionary innovation that occurred in the mammalian lineage after the divergence from sauropsids (14,15). Therefore, we propose the following revision of hair evolution at the molecular level: The last common ancestor of all extant amniotes contained cysteine-rich ␣-keratins, which served in the establishment of hard non-hair epidermal structures.…”

Section: Discussionmentioning

confidence: 99%

“…To determine the evolutionary implications of our data, the numbers of hard (cysteine-rich) keratins in various vertebrate species, as determined in this study and in previous reports (15,23), were mapped onto the phylogenetic tree of vertebrates (Fig. 6).…”

Section: Evolutionary History Of Hard Keratin Genes In Amniotesmentioning

confidence: 99%

“…Supporting a mammal-specific origin of hair, hair keratin genes have been reported to be absent from chicken and other nonmammalian species (14,15). So-called ␤-keratins, a family of sauropsid-specific proteins structurally unrelated to ␣-keratins but similar to mammalian keratin-associated proteins (16,17), are the main components of hard integumentary structures (scales, claws, beaks, feathers) of sauropsids.…”

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confidence: 99%

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Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair

Eckhart

Valle

Jaeger

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

105

135

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The appearance of hair is one of the main evolutionary innovations in the amniote lineage leading to mammals. The main components of mammalian hair are cysteine-rich type I and type II keratins, also known as hard ␣-keratins or ''hair keratins.'' To determine the evolutionary history of these important structural proteins, we compared the genomic loci of the human hair keratin genes with the homologous loci of the chicken and of the green anole lizard Anolis carolinenis. The genome of the chicken contained one type II hair keratin-like gene, and the lizard genome contained two type I and four type II hair keratin-like genes. Orthology of the latter genes and mammalian hair keratins was supported by gene locus synteny, conserved exon-intron organization, and amino acid sequence similarity of the encoded proteins. The lizard hair keratinlike genes were expressed most strongly in the digits, indicating a role in claw formation. In addition, we identified a novel group of reptilian cysteine-rich type I keratins that lack homologues in mammals. Our data show that cysteine-rich ␣-keratins are not restricted to mammals and suggest that the evolution of mammalian hair involved the co-option of pre-existing structural proteins.cytokeratin ͉ epidermis ͉ evolution ͉ reptiles ͉ claw

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Section: Discussionmentioning

confidence: 99%

Section: Evolutionary History Of Hard Keratin Genes In Amniotesmentioning

confidence: 99%

mentioning

confidence: 99%

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Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair

Eckhart

Valle

Jaeger

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

105

135

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“…LIII is the major lamin in oocytes. It is absent in mammals, 23 while somatic lamin C, a splice product of the lamin A gene (Fig. 1A), is restricted to mammals.…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of Xenopus lamin LIV reveals differences in the lamin composition of sperms in amphibians and mammals

Moeller

Barendziak

Apte

et al. 2010

Nucleus

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“…More than 50 keratin genes exist in the human genome, and the type I and type II keratin genes are clustered on chromosomes 17 and 12, respectively (Hesse et al, 2001;Schweizer et al, 2006). Other vertebrates, including the mouse, chicken, and clawed frog (Xenopus tropicalis), also have numerous type I and type II keratin genes clustered in their genomes (Zimek and Weber, 2005).…”

Section: Introductionmentioning

confidence: 99%

Characterization of a novel type I keratin gene and generation of transgenic lines with fluorescent reporter genes driven by its promoter/enhancer in Xenopus laevis

Suzuki

Kashiwagi

Ujihara

et al. 2010

Developmental Dynamics

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We investigated the characteristics of a novel type I keratin gene in Xenopus laevis during ontogenesis. The transcript was first detected in the posterior region at the late neurula stage, and then restricted to the fin and external gill during embryogenesis. To examine the transcriptional regulation of the keratin gene in vivo, we generated transgenic lines with fluorescent reporter genes driven by its 4.2-kb upstream sequence. The promoter/enhancer activity recapitulated the endogenous gene expression during embryogenesis. Sequential deletion analyses revealed that the regions proximal to the promoter were essential for fin-specific expression. Reporter expression was detected in various organs, including the fin and gill. In particular, robust expression was observed in the developing limbs and gill. The reporter fluorescence rapidly decreased with internal gill resorption during metamorphosis. The transgenic lines carrying the promoter/enhancer should represent valuable tools for elucidating the formation, development and resorption of various organs, especially the gill. Developmental Dynamics 239:3172-3181,

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Terrestrial vertebrates have two keratin gene clusters; striking differences in teleost fish

Cited by 44 publications

References 29 publications

Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair

Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair

Molecular characterization of Xenopus lamin LIV reveals differences in the lamin composition of sperms in amphibians and mammals

Characterization of a novel type I keratin gene and generation of transgenic lines with fluorescent reporter genes driven by its promoter/enhancer in Xenopus laevis

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