Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China.
Guangdong Provincial Fishery Germplasm Conservation Center, Guangzhou, 511400, China.
Fish Shellfish Immunol. 2020 Dec;107(Pt A):146-155. doi: 10.1016/j.fsi.2020.09.034. Epub 2020 Sep 28.
Mandarin fish (Siniperca chuatsi) is an important economic fish in China. Viral and bacterial diseases seriously affect the artificial culture of S. chuatsi. As a carnivorous fish, artificial feed domestication is also an important means to improve the scale of S. chuatsi culture. Therefore, the study of immunology and digestive physiology is very important to the industrial development of S. chuatsi. In this work, we analyzed the expression and function of the S. chuatsi leukocyte cell-derived chemotaxin 2 (Sc-lect2) gene on a basis of next generation, single-molecule long-read sequencing. Sc-lect2 was mainly expressed in the liver but barely expressed in the gill, skin, muscle, kidney, head kidney, brain, stomach, and intestine. When the fish were infected with infectious spleen and kidney necrosis virus and challenged with lipopolysaccharide and polyinosinic-polycytidylic acid, Sc-lect2 expression significantly increased by about 40, 17, and 7-fold, respectively, compared with unstimulated samples. We also found that Sc-lect2 increases by approximately 8-fold after the fish are fed an artificial diet. These results show that mandarin fish liver can not only digest food but also express specific immune genes. Changes in the diet can cause the differential expression of Sc-lect2 genes. Four Sc-lect2 interaction genes were differentially expressed in the skin or blood. Interestingly, miR-145-3p could inhibit Sc-lect2 gene expression by targeting its coding sequence region. One CpG island in the promoter region showed a high level of methylation, suggesting that high methylation does not affect Sc-lect2 gene expression in the liver.
鳜鱼（Siniperca chuatsi）是中国重要的经济鱼类。病毒和细菌性疾病严重影响鳜鱼的人工养殖。作为一种肉食性鱼类，人工饲料驯化也是提高鳜鱼养殖规模的重要手段。因此，免疫学和消化生理学的研究对鳜鱼的产业发展非常重要。在这项工作中，我们基于下一代、单分子长读测序技术，分析了鳜白细胞衍生趋化因子 2（Sc-lect2）基因的表达和功能。Sc-lect2 主要在肝脏中表达，但在鳃、皮肤、肌肉、肾脏、头肾、脑、胃和肠中几乎不表达。当鱼感染传染性脾肾坏死病毒并受到脂多糖和聚肌胞苷酸的刺激时，Sc-lect2 的表达分别比未刺激的样品增加了约 40、17 和 7 倍。我们还发现，当鱼被喂食人工饲料时，Sc-lect2 的表达增加了约 8 倍。这些结果表明，鳜鱼肝脏不仅可以消化食物，还可以表达特定的免疫基因。饮食的变化会导致 Sc-lect2 基因的差异表达。在皮肤或血液中，有 4 个 Sc-lect2 相互作用基因表达发生差异。有趣的是，miR-145-3p 可以通过靶向其编码序列区域抑制 Sc-lect2 基因的表达。启动子区域的一个 CpG 岛表现出高水平的甲基化，表明高甲基化并不影响肝脏中 Sc-lect2 基因的表达。
