State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Joint Laboratory for Deep Blue Fishery Engineering, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, China.
Fish Physiol Biochem. 2024 Aug;50(4):1513-1526. doi: 10.1007/s10695-024-01353-2. Epub 2024 May 9.
Leptins and other related genes have been proven to play vital roles in food intake, weight control, and other life activities. While the function of leptins in yellowtail kingfish (Seriola lalandi) has not yet been explored, in the present study, we investigated the structure and preliminary function of four leptin-related genes in S. lalandi. In detail, the sequence of two leptin genes (lepa and lepb), one leptin receptor gene (lepr), and one leptin receptor overlapping transcript (leprot) gene were obtained by homology cloning and RACE methods, in which lepa and lepb have similar structure. Moreover, homologous sequence alignment and evolutionary analysis of all four genes were clustered with Seriola dumerili. The tissue distribution of these four genes in thirteen tissues of yellowtail kingfish was detected by RT-qPCR. Both lepa and leprot were highly expressed in the brain and ovary, while lepb was highly expressed in the pituitary, gill, muscle, and ovary; lepr was highly expressed in the gill, kidney, and ovary. Additionally, these four genes also played roles in embryo development and early growth and development of larvae and juveniles of yellowtail kingfish. Finally, the function of leptin and leptin-related genes was investigated during fasting and re-feeding adaption of yellowtail kingfish. The results showed that these four genes have different regulation functions in five tissues; for example, the mRNA levels of lepa, lepr, and leprot in the brain decreased during fasting and immediately increased after re-feeding, while the mRNA level of lepb did not show significant fluctuation during starvation but significantly lowered after re-feeding. However, lepa and lepb mRNA levels were significantly elevated during fasting and returned to control levels after re-feeding, and there were no significant changes in the expression of lepr and leprot in the liver during fasting and after re-feeding. Moreover, the body mass of fish in the experimental group was measured, and compensatory growth was found after the resumption of feeding. These results suggested that leptin and receptor genes play different functions in different tissues to regulate the physiological state of fish in food deficiency and gain processes.
瘦素和其他相关基因已被证明在食物摄入、体重控制和其他生命活动中发挥着重要作用。虽然瘦素在黄尾鰤（Seriola lalandi）中的功能尚未被探索，但在本研究中，我们研究了 S. lalandi 中四个瘦素相关基因的结构和初步功能。详细地，通过同源克隆和 RACE 方法获得了两个瘦素基因（lepa 和 lepb）、一个瘦素受体基因（lepr）和一个瘦素受体重叠转录本（leprot）基因的序列，其中 lepa 和 lepb 具有相似的结构。此外，对所有四个基因进行了同源序列比对和进化分析，并与 Seriola dumerili 聚类。通过 RT-qPCR 检测了这四个基因在黄尾鰤 13 种组织中的组织分布。lepa 和 leprot 在脑中高度表达，而 lepb 在脑垂体、鳃、肌肉和卵巢中高度表达；lepr 在鳃、肾脏和卵巢中高度表达。此外，这四个基因在黄尾鰤胚胎发育和幼鱼早期生长发育中也发挥作用。最后，研究了瘦素和瘦素相关基因在黄尾鰤禁食和再投喂适应过程中的功能。结果表明，这四个基因在五个组织中有不同的调节功能；例如，禁食时脑中 lepa、lepr 和 leprot 的 mRNA 水平降低，再投喂后立即升高，而 lepb 的 mRNA 水平在饥饿时没有明显波动，但再投喂后显著降低。然而，禁食时 lepa 和 lepb 的 mRNA 水平显著升高，并在再投喂后恢复到对照水平，而在禁食和再投喂期间，肝脏中 lepr 和 leprot 的表达没有明显变化。此外，还测量了实验组鱼的体重，发现恢复进食后存在补偿性生长。这些结果表明，瘦素和受体基因在不同组织中发挥不同的功能，以调节鱼类在食物缺乏和获得过程中的生理状态。
