黑色素形成调控机理及乌骨绵羊黑色素沉积候选基因研究进展

黑色素(melanin)产生于黑色素细胞,是由酚类或吲哚类物质氧化聚合而成的不易溶于水的聚合体,广泛存在于微生物和动植物机体,具有消除自由基、抗氧化、抑制病毒感染、激活免疫系统、提高机体免疫力、延缓衰老等生理功能。酪氨酸在酪氨酸酶作用下生成多巴,多巴经过系列复杂的生物学反应形成黑色素。现有研究发现,多种信号通路(α-MSH/MC1R/cAMP信号通路、Wnt/β-catenin信号通路、PI3K/Akt/GSK3β信号通路、MAPK信号通路等)及相关调控因子(MITF、MC1R、TYR等)参与了黑色素的形成过程。一般认为,哺乳动物黑色素细胞主要分布于皮肤和毛囊组织,而乌骨绵羊的内脏组织也能存在大量黑色素细胞,其形成机制尚不明确。乌骨绵羊的乌质性状是重要的经济性状,与其营养和药用价值密切相关,受机体组织黑色素沉积程度的影响。文章简述了黑色素的理化性质、生物功能及其合成路径,回顾了近年来发现的调控动物机体黑色素合成的信号通路及其作用机理,总结了影响乌骨绵羊黑色素沉积和分布规律相关候选功能基因的研究现状,以期为深入研究黑色素沉积调控机理及候选功能基因应用于生产实践提供参考。

Research Progress on Mechanism of Melanin Deposition and Related Candidate Genes in Black-bone Sheep

Melanin, produced in melanocytes, is a water-insoluble polymer formed by the oxidative polymerization of phenols or indoles.It widely exists in microorganisms, animals and plants.It has the physiological functions of eliminating free radicals, antioxidation, inhibiting virus infection, activating immune system, improving body immunity and delaying aging.Under the effect of tyrosinase, tyrosine generates dopamine, dopamine forms melanin through a complex series of biological reactions.Existing studies have found that there are many signaling pathways (α-MSH/MC1R/cAMP signal pathway, Wnt/β-catenin signaling pathway, PI3K/Akt/GSK3β signal pathway, MAPK signal pathway, etc.) and related regulatory factors (MITF, MC1R, TYR, etc.) are involved in the formation of melanin.It is generally believed that mammalian melanocytes are mainly distributed in skin, hair follicles and other tissues, while a large number of melanocytes also exist in the visceral tissues of Black-bone sheep, and the formation mechanism of melanocytes was not clear yet.The character of Black-bone sheep is an important economic character, which is closely related to its nutritional and medicinal value and is affected by the degree of melanin deposition in body tissues.In this paper, the physical and chemical properties, biological functions, synthetic route and signaling pathways of melanin are reviewed, the research status of candidate functional genes affecting the deposition and distribution of melanin in Black-bone sheep are summarized.It is expected to provide reference for in-depth study of the regulation mechanism of melanin deposition and the application of candidate functional genes in production practice.