Expression Analysis of Melanogenesis Related Genes TYR, TYRP1 and DCT in Tobiano Mongolian Horse (Equus caballus) Skin Tissue
ZHAO Ruo-Yang1, LI Chao1, BAO Tuge-Qin1, MONGKE Togtokh1, Laxima1, WANG Wen-Xing2, HUANG Bo-Guang2, BAI Dong-Yi1,*, MANG Lai1,*
1 College of Animal Science, Inner Mongolia Key Laboratory of Equine Genetics/Breeding and Reproduction/Equine Research Center, Scientific Observing and Experimental Station of Equine Genetics/Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; 2 Inner Mongolia Zhong Yun Horse Industry Group, Xilinhot 026000, China
Abstract：Mammals coat color molecular mechanism has always been hotspot in animal genetics and breeding, variety of coat colors in nature arouse the interest of many researchers; horses (Equus caballus) with different complex colors, which is indispensable to the horse registration in breeding, and the molecular mechanisms of horse coat color is very important. Recent years, most researches are focused on breeds, few researches are from the perspective of the individuals and hair follicle pigment synthesis. Since Tobiano Mongolian Horse has unique coat color, the formation mechanism must be more complex. Pigment synthesis involves a large number of genes and complex regulatory networks. Tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), and tyrosinase-related protein 2 (TYRP2) which is now called dopachrome tautomerase (DCT) are 3 major genes at downstream of melanogenesis pathway. Paraffin-embedded tissue sections were stained with hematoxylin-eosin (HE) to analyze hair follicle structure and pigment distribution. qRT-PCR was used to detect the mRNA expression levels of TYR, TYRP1 and DCT genes in different color skins. The results showed Western blot (WB) and immunofluorescence (IF) were used to quantitatively locate their corresponding proteins. The pigment distribution in different color (black and white) skin tissues and the length of hair follicle dermal papillae was significantly different, meanwhile, the thickness of dermis was different, and the diameter of hair follicle hairball was slightly different. The mRNA and protein expressions of 3 genes were significantly different in different color skin tissues, and the protein expression was basically located in the hair matrix of hair follicle dermal papillae. The results showed TYR, TYRP1 and DCT, downstream genes of melanogenesis, might affect the synthesis of pigment in the different color skin tissues of Tobiano Mongolian horses, and can be the candidate regulatory factors in the process of hair pigment deposition. It will present information for the in-depth study of the molecular mechanism of Tobiano Mongolian Horse coat color and provide reference for other mammals.
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