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通过CRISPR敲除pmela和pmelb，通过调节色素细胞的相对丰度，培育出了金黄色罗非鱼 黑素前蛋白(pmel)是脊椎动物黑素发生的关键基因。这种基因的突变导致了鸡的白色羽毛，但它在鱼类色素沉着中的作用仍有待证实。在本研究中，我们发现大多数鱼类有两个pmel基因来自硬骨鱼特有的全基因组复制。pmela和pmelb在尼罗罗非鱼的眼睛和皮肤中均有高水平表达。我们使用CRISPR/Cas9基因编辑技术使这两个基因在罗非鱼体内发生突变。pmela纯合子突变导致体色偏黄，竖条较弱，视网膜色素上皮色素降低(RPE)，因为黑色素细胞的数量和大小明显减少。相比之下，我们观察到突变体中黄色素的数量和大小都比野生型鱼多。pmelb纯合突变的结果与pmela -/-突变体相似，但表型更温和，对RPE色素沉着没有影响。与pmela -/-突变体相比，pmela和pmelb双突变体的黑素细胞数量减少，黄素细胞数量和大小增加，躯干呈金黄色，无条状。pmelb -/-突变体和pmelb -/-突变体的RPE色素沉着与pmelb -/-突变体相似，但明显低于pmelb -/-突变体和野生型。综上所述，我们的结果表明，虽然两个pmel基因在罗非鱼体色的形成中都很重要，但pmela基因的作用比pmelb基因更重要。据我们所知，这是首次在鱼类中发现pmelb或pmelb突变。这些突变体的研究为金罗非鱼的选育提供了新的策略，也为研究脊椎动物的pmel功能提供了新的模型。 Premelanosome protein (pmel) is a key gene for melanogenesis in vertebrates. Mutations in this gene are responsible for white plumage in chicken, but its role in pigmentation of fish remains to be demonstrated. In this study we found that most fishes have two pmel genes arising from the teleost-specific whole genome duplication. Both pmela and pmelb were expressed at high levels in the eyes and skin of Nile tilapia. We mutated both genes in tilapia using CRISPR/Cas9 gene editing. Homozygous mutation of pmela resulted in yellowish body color with weak vertical bars and a hypo-pigmented retinal pigment epithelium (RPE) due to significantly reduced number and size of melanophores. In contrast, we observed an increased number and size of xanthophores in mutants compared to wild-type fish. Homozygous mutation of pmelb resulted in a similar, but milder phenotype than pmela -/- mutants, without effects on RPE pigmentation. Double mutation of pmela and pmelb resulted in loss of additional melanophores compared to the pmela -/- mutants, and also an increase in the number and size of xanthophores, producing a strong golden body color without bars in the trunk. The RPE pigmentation of pmela -/ - ;pmelb -/- was similar to pmela -/- mutants, with much less pigmentation than pmelb -/- mutants and wild-type fish. Taken together, our results indicate that, while both pmel genes are important for the formation of body color in tilapia, pmela plays a more important role than pmelb. To our knowledge, this is the first report on mutation of pmelb or both pmela;pmelb in fish. Studies on these mutants suggest new strategies for breeding golden tilapia, and also provide a new model for studies of pmel function in vertebrates.  文章来源网络整理；如有侵权请及时联系PaperRSS小编删除，转载请注明来源。 温馨提示： 为方便PaperRSS粉丝们科研、就业等话题交流。我们根据10多个专业方向（植物、医学、药学、人工智能、化学、物理、财经管理、体育等），特建立了30个国内外博士交流群。群成员来源欧美、日韩、新加坡、清华北大、中科院等全球名校。 |
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