Morphogenesis of Compound Melanosomes in Melanoma Cells of a Gray Horse

Ohmuro, Kenji; Okada, Kōsuke; Satoh, Akira; Murakami, Kenji; Satake, Shigeru; Asahina, Masatoshi; Numakunai, Shigeru; Ohshima, Kan-ichi

doi:10.1292/jvms.55.677

Cited by 11 publications

(5 citation statements)

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“…Whether a lack of dendrites in dermal melanocytes of grey horses and therefore a cellular transport problem for melanin pigment from the melanocyte to the hairshaft or a break in melanin biosynthesis is responsible for the progressive loss of coat colour is still not known. The manner in which these events are even connected to the malignant melanocyte‐specific process occurring in some of the older grey horses is also unknown (Gebhart and Niebauer 1977; Foley et al 1991; Ohmuro et al 1993; Valentine 1995; Rodriguez et al 1997; Rieder 1999).…”

Section: Introductionmentioning

confidence: 99%

A comparative genetic approach for the investigation of ageing grey horse melanoma

Rieder

Stricker

Joerg

et al. 2000

J Animal Breeding Genetics

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Ageing grey horses are particularly susceptible to melanoma. Using segregation analysis, six genetic and nongenetic (environmental) models in two grey horse family groups (n = 71) were compared. The polygenic model still fits the data significantly better than an environmental model, indicating a strong genetic impact on the phenomenon. Pmel17/gp100 and TYRP1/gp75, two genes which are specific for melanocytes, and Cdkn2a/p16 a gene coding for an inhibitor of a cell cycle regulator were partially cloned, sequenced and mapped. Using Northern blotting analysis a striking difference in mRNA expression of Pmel17/gp100 and TYRP1/gp75 was found comparing skin samples of solid-coloured (normal level) and grey horses (low level) as well as horse melanoma tumour samples (high). Staining of skin samples with antibodies recognizing the product of Pmel17/gp100, confirmed the results of the corresponding Northern blotting analysis. It seems that Pmel17/gp100 and TYRP1/gp75 are involved in progressive greying of horses. No mutation was found in a partial sequence of equine Cdkn2a/p16 analysed so far. Thus, the relation between equine melanoma susceptibility and Cdkn2a/p16 is subject to further investigation. ZusammenfassungAlternde echte Schimmel sind unabhängig von Geschlecht, Rasse und Population auffällig oft von Hautmelanomen betroffen. Phänotypische Daten zweier Schimmel-Pferdefamilien (n = 71) wurden mittels einer Segregationsanalyse auf sechs genetische und nicht-genetische Modelle ü berprü ft. Die Daten passten sich dem rein polygenen Modell immer noch signifikant besser an als dem Umweltmodell. Dies deutet auf einen starken genetischen Einfluss fü r dieses Merkmal hin. Pmel17/gp100 und TYRP1/gp75, zwei melanozytenspezifische Gene, und Cdkn2a/p16 ein Gen welches einen Inhibitor der Zellzyklusregulation codiert, wurden partiell kloniert, sequenziert und kartiert. Eine 'Northern blot' Analyse zeigte beim Vergleich von Hautproben zwischen farbigen Pferden (normal), Schimmeln (keine) und Tumoren (stark) signifikante Unterschiede in der mRNA-Expression von Pmel17/gp100 und TYRP1/gp75. Färbungen von Hautproben mit einem Antikö rper spezifisch fü r das Produkt von Pmel17/gp100 bestätigten diese Expressionsstudie. Demnach scheint es, dass Pmel17/gp100 und TYRP1/gp75 Einfluss auf die progressive Vergrauung bei Pferden ausü ben. In der partiellen Sequenz von Cdkn2a/p16 wurden bis jetzt keine Mutationen gefunden. Der Zusammenhang zwischen melanomanfälligen grauen Pferden und Cdkn2a/p16 bleibt Gegenstand weiterer Untersuchungen. RésuméLa mélanose concerne plus particulièrement les chevaux gris adultes. Par une analyse de ségrégation, six modèles génétiques et nongénétiques (environnement) ont été comparés dans deux familles de chevaux gris (n = 71). Les données s'ajustent significativement mieux au modèle polygène par rapport au modèle environnemental, ce qui implique un effet génétique important. Deux loci exprimés spécifi-quement dans le mélanocyte -Pmel17/gp100 et TYRP1/gp75 -et un locus codant pour un inhibiteur du cycle cellul...

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Section: Introductionmentioning

confidence: 99%

A comparative genetic approach for the investigation of ageing grey horse melanoma

Rieder

Stricker

Joerg

et al. 2000

J Animal Breeding Genetics

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“…It is known that by to 80% of aged gray horses show signs of melanoma [5,11,13]. Moreover, there is a report stating that horse melanomas are considered to be different in their pathological characteristics from human melanomas [4].…”

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confidence: 99%

Establishments and Biological Characteristics of Melanoma Culture Cell Lines Derived from Aged Gray Horses.

Ishikawa

Mukoyama

Matsuura

et al. 2000

JES

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“…As neoplasias cutâneas representam 50% das neoplasias encontradas em equinos (VALENTINE, 2006). Destas, 15% são de origem melanocítica (OHMURO et al, 1993;GOLDSCHMIT;MCMANUS, 2002). Porém, seu diagnóstico histopatológico é feito em apenas 3,8% dos casos nesta espécie (SUNDBERG et al, 1977).…”

Section: Estudo De Neoplasias Melanocíticas Em Equinosunclassified

“…Desde o início do século XX são descritos casos de neoplasia melanocítica em cavalos tordilhos (SELTENHAMMER et al, 2003) e geralmente se iniciam em animais entre cinco e dez anos de idade, época em que ocorre a troca de pelos escuros por mais claros (OHMURO et al, 1993;FLEURY et al, 2000b;GOLDSCHMITH;MCMANUS, 2002).…”

Section: Estudo De Neoplasias Melanocíticas Em Equinosunclassified

“…A melanogênese ocorre em melanossomos, organelas delimitadas por membranas, que utilizam a tirosina como substrato, convertendo-se em dopa e dopaquinona pela tirosinase (HARGIS, 1998). A melanina não fica retida no melanócito normal, sendo transferida a partir dos processos dendríticos do melanócito para os queratinócitos adjacentes, na forma de melanossomos, por um mecanismo de endocitose (OHMURO et al, 1993). Os melanossomos são dispostos sob a forma de capuz sobre o núcleo dos queratinócitos, ajudando a protegê-los da luz ultravioleta.…”

Section: Gênese Do Melanomaunclassified

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Expressão de marcadores imunoistoquímicos em neoplasias melanocíticas de equinos por microarranjo de tecidos

Landman¹

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Morphogenesis of Compound Melanosomes in Melanoma Cells of a Gray Horse

Cited by 11 publications

References 0 publications

A comparative genetic approach for the investigation of ageing grey horse melanoma

A comparative genetic approach for the investigation of ageing grey horse melanoma

Establishments and Biological Characteristics of Melanoma Culture Cell Lines Derived from Aged Gray Horses.

Expressão de marcadores imunoistoquímicos em neoplasias melanocíticas de equinos por microarranjo de tecidos

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