Knockout of microphthalmia-associated transcription factor (mitf) confers a red and yellow tilapia with few pigmented melanophores
Knockout of microphthalmia-associated transcription factor (mitf) confers a red and yellow tilapia with few pigmented melanophores
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DOI：
10.1016/j.aquaculture.2022.739151
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发表时间：
2022-12
期刊：
影响因子：
4.5
通讯作者：
Chenxu Wang;T. Kocher;Jinzhi Wu;Pengfei Li;Guangyuan Liang;Baoyue Lu;Jia Xu;Xiaoke Chen
中科院分区：
文献类型：
--
作者：
Chenxu Wang;T. Kocher;Jinzhi Wu;Pengfei Li;Guangyuan Liang;Baoyue Lu;Jia Xu;Xiaoke Chen
作为黑素细胞分化和黑素合成的最重要的遗传因子，mitf的研究已有30多年的历史。近世纪来，mitf突变体的表型也一直受到人们的关注。由于第三轮基因组复制，硬骨鱼有两个缺失基因。突变分析表明mitfa在斑马鱼色素形成中起重要作用。然而，目前还没有通过mitfb或mitfa; mitfb双突变体研究体色调节的功能。在本研究中，我们使用CRISPR/Cas9突变罗非鱼中的两个thmitf基因。由于黑色素细胞数量显著减少和黄色素细胞大小增加，线粒体的破坏导致浅黄色的体色和弱灰色的竖条，而线粒体的破坏导致轻微的色素沉着减退。mitfa和mitfb的双突变导致躯干和鳍的色素减少，这是由于与单突变体相比，额外的黑色素细胞的丢失和虹膜细胞数量的增加，但对视网膜色素上皮（RPE）色素没有影响。Themitfa−/−; mitfb−/−突变体在幼年早期（60 dpf）为黄色带黑色斑点，在幼年晚期（120 dpf）为黄红色，在成年期（180 dpf）为红色和黄色（包括虹膜），这是由于红细胞增加和黄细胞增大。结果表明，两个mitf基因在罗非鱼体色形成中均起重要作用，但mitfa基因的作用比mitfb基因的作用更大。pmelb-/-和hps 4-/-突变体，我们发现，黑素合成不同方面的不同功能基因的破坏可以导致罗非鱼不同的体色。Mitfis是黑素细胞分化的最重要基因，可能是也是红细胞、黄细胞和虹膜细胞分化的关键。据我们所知，这是第一份通过功能丧失研究表明两个mitf基因都参与体色形成的报告，也是第一份表明mitf影响红细胞数量和黄细胞大小的报告。本研究不仅为研究罗非鱼及其近缘种慈鲷的线粒体功能提供了模型，而且为养殖红、黄罗非鱼提供了新的策略。
As the most important genetic factor for melanophore differentiation and melanogenesis,mitfhas been studied for over 30 years. The phenotypes ofmitfmutants have also received continuous attention for nearly a century. Due to the third round of genome duplication, teleosts have twomitfgenes. Mutation analysis demonstrates thatmitfaplays an important role in zebrafish pigmentation. However, there have been no functional studies on body color regulation bymitfbor studies ofmitfa;mitfbdouble mutants. In the present study, we mutated bothmitfgenes in tilapia using CRISPR/Cas9. Disruption ofmitfaresulted in light yellow body color with weak gray vertical bars due to significantly reduced numbers of melanophores and increased sizes of xanthophores, while disruption ofmitfbled to slight hypo-pigmentation. Double mutation ofmitfaandmitfbresulted in dramatic hypo-pigmentation in trunk and fins due to loss of additional melanophores and increase in the number of iridophores compared to the single mutants, but had no influence on retinal pigment epithelium (RPE) pigmentation. Themitfa−/−;mitfb−/−mutants were yellow with black spots at early juvenile stage (60 dpf), yellow-reddish at late juvenile stage (120 dpf) and red and yellow (including iris) at adult stage (180 dpf), due to increased erythrophores and enlarged xanthophores. Our results demonstrated that bothmitfgenes are important for body color formation in tilapia, butmitfaplays a more important role thanmitfb.Additionally, by comparing the phenotypes of themitfa−/−;mitfb−/−,pmela−/−;pmelb−/−andhps4−/−mutants, we found that disruption of genes with different functions in different aspects of melanogenesis could lead to different body colors in tilapia.Mitfis the most important gene for melanophore differentiation and is probably also critical for differentiation of erythrophores, xanthophores and iridophores. To our knowledge, this is the first report showing that bothmitfgenes are involved in body color formation by loss of function study, and the first report showing that erythrophore numbers and xanthophore sizes were affected bymitf. Our research not only serves as a model for studyingmitffunction in tilapia and the closely related cichlids, but also provides new strategies for breeding red and yellow tilapia for aquaculture.