Pigmentary function and evolution of <i>tyrp1</i> gene duplicates in fish

Braasch, Ingo; Liedtke, Daniel; Volff, Jean Nicolas; Schartl, Manfred

doi:10.1111/j.1755-148x.2009.00614.x

Cited by 86 publications

(63 citation statements)

References 57 publications

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“…Knockdown of the zebrafish orthologues tyr (TYR), oca21p (OCA2), tyrp1a and tyrp1b simultaneously (TYRP1), slc45a2 (SLC45A2), slc24a5 (SLC24A5), or c10orf11 (C10ORF11) lead to a reduction or complete absence of melanin in the eye, with varying responses to visual testing immediately after light exposure, phenocopying the varying degrees of hypopigmentation of the eyes of OCA patients and exemplifying the use of zebrafish to model human pathologies of the eye. [65][66][67][68][69] Multiple zebrafish mutants have been identified with visual defects secondary to functional deficits in the RPE. The vps39 mutant carries a mutation in the zebrafish orthologue of VPS39, a gene encoding a component of the vacuole protein sorting (HOPS) membrane-tethering complex, which coordinates vesicle fusion and transport.…”

Section: Ocular Albinism and Associated Syndromesmentioning

confidence: 99%

The zebrafish eye—a paradigm for investigating human ocular genetics

Richardson¹,

Tracey‐White²,

Webster

et al. 2016

Eye

153

162

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Although human epidemiological and genetic studies are essential to elucidate the aetiology of normal and aberrant ocular development, animal models have provided us with an understanding of the pathogenesis of multiple developmental ocular malformations. Zebrafish eye development displays in depth molecular complexity and stringent spatiotemporal regulation that incorporates developmental contributions of the surface ectoderm, neuroectoderm and head mesenchyme, similar to that seen in humans. For this reason, and due to its genetic tractability, external fertilisation, and early optical clarity, the zebrafish has become an invaluable vertebrate system to investigate human ocular development and disease. Recently, zebrafish have been at the leading edge of preclinical therapy development, with their amenability to genetic manipulation facilitating the generation of robust ocular disease models required for large-scale genetic and drug screening programmes. This review presents an overview of human and zebrafish ocular development, genetic methodologies employed for zebrafish mutagenesis, relevant models of ocular disease, and finally therapeutic approaches, which may have translational leads in the future.

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Section: Ocular Albinism and Associated Syndromesmentioning

confidence: 99%

The zebrafish eye—a paradigm for investigating human ocular genetics

Richardson¹,

Tracey‐White²,

Webster

et al. 2016

Eye

153

162

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“…As part of the differentiation programme, melanocytes express pigmentation enzymes, including tyrosinase related protein (Tyrp) 1 (Braasch et al, 2009;Smyth et al, 2006;Steel et al, 1992). We analyzed developing melanocytes in the zebrafish j900 line that expresses GFP from the fugu tyrp1 promoter in the neural crestderived melanocytes (Hultman and Johnson, 2010).…”

Section: Dividing Embryonic Melanocytes Give Rise To Pigmented Dendrimentioning

confidence: 99%

Differentiated melanocyte cell division occurs in vivo and is promoted by mutations in Mitf

Taylor

Lister

Zeng³

et al. 2011

Development

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SUMMARYCoordination of cell proliferation and differentiation is crucial for tissue formation, repair and regeneration. Some tissues, such as skin and blood, depend on differentiation of a pluripotent stem cell population, whereas others depend on the division of differentiated cells. In development and in the hair follicle, pigmented melanocytes are derived from undifferentiated precursor cells or stem cells. However, differentiated melanocytes may also have proliferative capacity in animals, and the potential for differentiated melanocyte cell division in development and regeneration remains largely unexplored. Here, we use time-lapse imaging of the developing zebrafish to show that while most melanocytes arise from undifferentiated precursor cells, an unexpected subpopulation of differentiated melanocytes arises by cell division. Depletion of the overall melanocyte population triggers a regeneration phase in which differentiated melanocyte division is significantly enhanced, particularly in young differentiated melanocytes. Additionally, we find reduced levels of Mitf activity using an mitfa temperature-sensitive line results in a dramatic increase in differentiated melanocyte cell division. This supports models that in addition to promoting differentiation, Mitf also promotes withdrawal from the cell cycle. We suggest differentiated cell division is relevant to melanoma progression because the human melanoma mutation MITF 4T⌬2B promotes increased and serial differentiated melanocyte division in zebrafish. These results reveal a novel pathway of differentiated melanocyte division in vivo, and that Mitf activity is essential for maintaining cell cycle arrest in differentiated melanocytes.

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“…Moreover, TYRP1 plays a well-established and crucial role in mammalian pigmentation and refers to the classic brown locus in mice Zdarsky et al, 1990;Javerzat and Jackson, 1998). Mutations in TYRP1 are repeatedly associated with brownish coat colour in a number of domestic animals, including cat (Lyons et al, 2005;Schmidt-Kuntzel et al, 2005), dog (Schmutz et al, 2002), cattle (Berryere et al, 2003), and sheep (Gratten et al, 2007), as well as quail (Nadeau et al, 2007) and fish (Braasch et al, 2009). We, therefore, selected TYRP1 as the prime candidate gene and investigated whether mutations in TYRP1 might be responsible for the brown phenotypes in Chinese pig breeds.…”

Section: Resultsmentioning

confidence: 99%

A 6-bp deletion in the TYRP1 gene causes the brown colouration phenotype in Chinese indigenous pigs

et al. 2010

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Brown coat colour has been described in Chinese-Tibetan, Kele, and Dahe pigs. Here, we report the identification of a causal mutation underlying the brown colouration. We performed a genome-wide association study (GWAS) on Tibetan and Kele pigs, and found that brown colours in Chinese breeds are controlled by a single locus on pig chromosome 1. By using a haplotype-sharing analysis, we refined the critical region to a 1.5-Mb interval that encompasses only one pigmentation gene: tyrosinaserelated protein 1 (TYRP1). Mutation screens of sequence variants in the coding region of TYRP1 revealed a strong candidate causative mutation (c.1484_1489del).The protein-altering deletion showed complete association with the brown colouration across Chinese-Tibetan, Kele, and Dahe breeds by occurring exclusively in brown pigs (n ¼ 121) and lacking in all non-brown-coated pigs (n ¼ 745) from 27 different breeds. The findings provide the compelling evidence that brown colours in Chinese indigenous pigs are caused by the same ancestral mutation in TYRP1. To our knowledge, this study gives the first description of GWAS identifying causal mutation for a monogenic trait in the domestic pig.

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Pigmentary function and evolution of tyrp1 gene duplicates in fish

Cited by 86 publications

References 57 publications

The zebrafish eye—a paradigm for investigating human ocular genetics

The zebrafish eye—a paradigm for investigating human ocular genetics

Differentiated melanocyte cell division occurs in vivo and is promoted by mutations in Mitf

A 6-bp deletion in the TYRP1 gene causes the brown colouration phenotype in Chinese indigenous pigs

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