摘　要：斑马鱼（Danio rerio）是一种常见的模式生物，红斑马鱼为小型观赏性鱼类之一。鱼类体色主要是由皮肤或鳞片上的色素细胞的种类和分布决定的。黑色素细胞诱导转录因子（MITF）主要调控动物黑色素细胞发育和分化。本文观察了红斑马鱼成鱼的背鳍、臀鳍、腹鳍、胸鳍色素细胞的组成和分布，跟踪观察了红斑马鱼早期体色发育过程。通过CRISPR/Cas9基因敲除技术构建了mitfa基因敲除体系，研究了mitfa基因在红斑马鱼早期体色发育中的作用。结果表明：1）红斑马鱼鳍上分布有红色素细胞、黄色素细胞和少量的虹彩细胞，但背鳍有大量的黑色素细胞；2）在红斑马鱼早期体色发育过程中，首先出现黑色素细胞，接着出现黄色素细胞，一个月后，红斑马鱼的黑色素细胞消退，鱼体表变浅红，变色中体表颜色逐渐加深，最后呈红色、银白色条纹相间分布的成鱼体色；3）利用CRISPR/Cas9技术，敲除mitfa基因，结果发现，mitfa的缺失导致早期红斑马鱼黑色素细胞显著减少。上述研究结果将为观赏鱼的选育以及建立人工改良鱼类体色有效途径提供重要的理论支撑。
关键词：红斑马鱼；鱼鳍；mitfa；CRISPR/Cas9；色素细胞
中国分类号：Q789                             文献标志码：ADOI：10.3969/j.issn.1007-7146.2022.01.004

Abstract: Zebrafish (Danio rerio) is a common model organism, red zebrafish is one of the small ornamental fishes. The body color of fish is mainly determined by the tape and distribution of pigments on the skin or scales. Melanocytes inducing transcription factor (MITF) mainly regulate the development and differentiation of animal melanocytes. We observed the composition and distribution of pigment cells in the dorsal, anal, pelvic, ectoral of adult red zebrafish, and tracked the early body color development process of the red zebrafish. The knockouting system of mitfa gene was constructed by CRISPR/Cas9 gene knockout technology, which is to study how mitfa gene plays a role in early color development of red zebrafish. The results showed that: 1) Red pigment cells, xanthophores and a small amount of iridophores cells are distributed on the red zebrafish fin, but there are a large number of melanocytes in the dorsal fin; 2) During the early body color development of the red zebrafish, melanocytes appear first and then xanthophores appeared. One month later, the melanocytes of the red zebrafish faded, and the surface of the fish became light red. Then the color of the body surface gradually deepened during the discoloration, and finally the body color of the adult fish with red and silver-white stripes alternately distributed; 3) Using CRISPR/Cas9 technology to knock out the mitfa gene, it was found that the absence of mitfa resulted in significantly fewer melanocytes in the early red zebrafish. The above research results will provide important theoretical support for the selection and breeding of ornamental fish and the establishment of effective ways to artificially improve the body color of fish.
Key words: red zebrafish; fins; mitfa; CRISPR/Cas9; pigment cells
（Acta Laser Biology Sinica, 2022, 31(1): 019-026）