<i>TYR</i> Gene in Llamas: Polymorphisms and Expression Study in Different Color Phenotypes
Tyrosinase, encoded by <i>TYR</i> gene, is an enzyme that plays a major role in mammalian pigmentation. It catalyzes the oxidation of L-dihydroxy-phenylalanine (DOPA) to DOPA quinone, a precursor of both types of melanin: eumelanin and pheomelanin. <i>TYR</i> is commonly know...
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| Autores principales: | , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2019
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/107981 http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC6582663&blobtype=pdf https://www.frontiersin.org/articles/10.3389/fgene.2019.00568/full |
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| Sumario: | Tyrosinase, encoded by <i>TYR</i> gene, is an enzyme that plays a major role in mammalian pigmentation. It catalyzes the oxidation of L-dihydroxy-phenylalanine (DOPA) to DOPA quinone, a precursor of both types of melanin: eumelanin and pheomelanin. <i>TYR</i> is commonly known as the <i>albino</i> locus since mutations in this gene result in albinism in several species. However, many other <i>TYR</i> mutations have been found to cause diluted phenotypes, like the Himalayan or chinchilla phenotypes in mice. The llama (<i>Lama glama</i>) presents a wide variety of coat colors ranging from non-diluted phenotypes (eumelanic and pheomelanic), through different degrees of dilution, to white. To investigate the possible contribution of <i>TYR</i> gene to coat color variation in llamas, we sequenced <i>TYR</i> exons and their flanking regions and genotyped animals with diluted, non-diluted, and white coat, including three blue-eyed white individuals. Moreover, we analyzed mRNA expression levels in skin biopsies by qPCR. <i>TYR</i> coding region presented nine SNPs, of which three were non-synonymous, c.428A > G, c.859G > T, and c.1490G > T. We also identified seven polymorphisms in non-coding regions, including two microsatellites, an homopolymeric repeat, and five SNPs: one in the promoter region (c.1-26C > T), two in the 3'-UTR, and two flanking the exons. Although no complete association was found between coat color and SNPs, c.1-26C > T was partially associated to diluted phenotypes. Additionally, the frequency of the G allele from c.428A > G was significantly higher in white compared to non-diluted. Results from qPCR showed that expression levels of TYR in white llamas were significantly lower (p < 0.05) than those in diluted and non-diluted phenotypes. Screening for variation in regulatory regions of TYR did not reveal polymorphisms that explain such differences. However, data from this study showed that TYR expression levels play a role in llama pigmentation. |
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