Characterization and expression analysis of KIT and MITF‐M genes in llamas and their relation to white coat color

Abstract

The llama (Lama glama) is a fiber-producing species that presents a wide range of coat colors, among which white is one of the most important for the textile industry. However, there is little information about the molecular mechanisms that control the white phenotype in this species. In domestic mammals, a white coat is usually produced by mutations in the KIT proto-oncogene receptor tyrosine kinase (KIT) and microphthalmia-associated transcription factor (MITF) genes. In this work we have sequenced and described the coding regions of KIT and MITF-M, the melanocyte-specific isoform, and the two transcriptional variants MITF-M(À) and MITF-M(+). Moreover, we studied the expression of these genes in the skin of white and colored llamas. Although no variants were revealed to be associated with white coat color, significant differences between phenotypes were observed in the expression levels of KIT and MITF-M. Interestingly, white llamas expressed less MITF-M(+) than did colored ones, which is consistent with a consequent reduction in the synthesis of melanin. Even though our results indicate that downregulation of KIT and MITF-M expression is involved in white phenotype production in llamas, the causative gene of white coat color remains unknown.

TYR Gene in Llamas: Polymorphisms and Expression Study in Different Color Phenotypes

“…We found that TYR was significantly less expressed in the WHITE group compared to NON-DILUTED. This was expected, since MITF-M gene, which regulates TYR expression, was found to be less expressed in white llamas compared to colored ones (Anello et al, 2019). Our results are also consistent with the observations of Paterson et al (2015), who demonstrated that partial depletion of TYR inhibited melanosome maturation and the expression of genes that regulates melanogenesis, altering mouse coat color.…”

“…We also studied KIT and MITF-M genes and their relation to white coat. Although no variants were found to be associated with white phenotype, both genes were less expressed in this phenotype (Anello et al, 2019). Here, we aimed to study the possible contribution of TYR gene to coat color variation in llamas and to do so, we describe the TYR gene, its variation, and its skin expression.…”

Chromosomal Localization of Candidate Genes for Fiber Growth and Color in Alpaca (Vicugna pacos)

“…Furthermore, SOX9 is a key player in ultraviolet B radiation-induced melanocyte differentiation and pigmentation by directly regulating MITF (Passeron et al, 2007). MITF is involved in melanogenesis regulation in alpaca (Wang et al, 2017) and plays a role in the production of white coat color in the llama (Anello et al, 2019). Finally, ALX3 is involved in color differentiation in striped rodents (Cuthill et al, 2017), and proposed as a target melanoma gene fusion in humans (Berger et al, 2010).…”

Genome‐wide search reveals the uniqueness of DNA regions associated with coat color and innate immunity in Hokkaido Native Horse

“…Both of these regions overlapped with the region encoding KIT Proto‐Oncogene, Receptor Tyrosine Kinase gene ( KIT ) (77,728,139 to 77,809,750), which regulates the development of melanocytes (Grichnik, 2006). Mutations of the KIT cause white markings on fur because of pigment loss in many mammalian species (Anello et al, 2019; Brenig et al, 2013; Hu et al, 2020; Sun et al, 2020). The relationship between mutations of KIT and the size of white markings has been reported in many horse breeds, for example, the g.79574583 (c.2045G > A) and g.77784972T > C mutations in KIT have been reported to be related to the size of white markings on the forehead and limbs of Spanish purebred horses (Haase et al, 2013; Negro et al, 2017; Patterson Rosa et al, 2022).…”