Abstract: MC1R is one important gene that affects the melanin system in skin pigmentation, and the melanogenesis is also affected by the interaction of molecular signals extracellular and intracellular. To explore the biological characteristics of MC1R in Youzhou dark goat, the cDNA sequence of MC1R form the skin of Youzhou dark goat was amplified and identified using the bioinformatics analysis. The results were as follows: the CDS of Youzhou dark goat MC1R gene is 954 bp in length and encodes 317 amino acids, there was highly homologous of MC1R in Youzhou dark goat with other various species. Its molecular formula was C₁₆₀₃H₂₅₆₅N₄₁₁O₄₁₀S₂₂. The encoded protein was a stable hydrophobic protein, including seven transmembrane regions and three functional domains. The primary secondary structure of MC1R was mainly used to compose the α-helix. In addition, a SNP (c.676A>G) has been found in Youzhou dark goat MC1R gene, and resulted in the conversation of lysine to glutamate, which is located in a conserved domain bound by light stimulation and G protein ligand. Meanwhile, the nonsynonymous substitution of amino acids also caused the different of spatial conformation of MC1R. Polymorphism detection showed that the SNP of c.676A >G in the MC1R gene of goats was also found among HeChuan white goats, WuXi white goats, Youzhou white goats and Youzhou dark goats in Chongqing, and the genotype of c.676A>G was not significantly different in the white and black goat populations (P>0.05). The study preliminarily revealed the sequence characteristics and protein structure of MC1R in Youzhou dark goat, and provided theoretical data for the molecular mechanism of the effect of MC1R on skin pigment deposition in Youzhou dark goat.

Key words: MC1R gene, amplification, Youzhou dark goat, genetic diversity analysis

摘要： MC1R是影响皮肤色素沉着中黑皮素系统的重要基因,通过信号分子的相互作用影响黑色素的生成。为探究酉州乌羊 MC1R的生物学特性,本研究对酉州乌羊MC1R进行了分离鉴定、生物信息学分析。结果表明,酉州乌羊皮肤组织MC1R基因的CDS序列为954 bp,共编码317个氨基酸,酉州乌羊与各物种MC1R具有较高同源性。酉州乌羊MC1R编码蛋白的分子式是C₁₆₀₃H₂₅₆₅N₄₁₁O₄₁₀S₂₂,其为疏水蛋白,有7个α-螺旋组成的跨膜结构域和3个保守功能结构域,MC1R氨基酸序列大部分都用于构成α-螺旋。此外,酉州乌羊MC1R基因c.676A>G突变,其编码的氨基酸由赖氨酸转变为谷氨酸,位于受光刺激和G蛋白配体结合的保守结构域上,氨基酸的异义替换还造成了酉州乌羊MC1R空间构象的差异。而对重庆市山羊群体多态性检测发现,山羊MC1R基因c.676A>G变异位点在重庆合川白山羊、巫溪白山羊、本地白山羊、酉州乌羊中共享,且c.676A>G位点的各基因型在皮肤白色和乌色山羊群体中的分布差异不显著(P>0.05)。本研究初步揭示酉州乌羊MC1R的序列特征和蛋白结构,为酉州乌羊MC1R影响皮肤色素沉积的分子机制研究提供了理论数据。

关键词: MC1R基因, 克隆, 酉州乌羊, 遗传多态性分析