National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China; International Research Center for Marine Biosciences, Shanghai Ocean University, Ministry of Science and Technology, Shanghai 201306, China.
Comp Biochem Physiol B Biochem Mol Biol. 2021 Oct-Dec;256:110627. doi: 10.1016/j.cbpb.2021.110627. Epub 2021 May 29.
Urotensin I (UI), a member of the corticotropin-releasing hormone family of peptides, regulates a diverse array of physiological functions, including appetite regulation, defensive behavior and stress response. In this study, firstly, the tissue-specific distribution of UI mRNA in olive flounder (Paralichthys olivaceus) was characterized and we found that UI mRNA was highly expressed in caudal neurosecretory system (CNSS) tissue. Secondly, alignment analysis found that a conserved cAMP response binding (CREB) site and a TATA element were located in the proximal promoter of UI gene. In addition, treatment of forskolin activatated cAMP-CREB pathway and induced the up-regulation of UI mRNA in cultured CNSS, suggesting the role of CREB in regulating the UI mRNA expression. Furthermore, plasma UI concentration and UI mRNA in CNSS showed obvious daily rhythm, with higher values in the daytime while lower values in the nighttime. Thirdly, using bold personality (BP) and shy personality (SP) flounder as an animal model, we found that flounder exhibited significantly higher locomotor activity in the nighttime than in the daytime (P < 0.001), and BP flounder showed significantly higher locomotor activity (P < 0.001) compared with SP flounder both in the daytime and nighttime. Analysis of feeding behavior revealed that BP flounder showed a shorter latency to feed and more attacks to prey. Furthermore, the qPCR and immunohistochemistry results showed that BP flounder expressed significantly lower level of UI mRNA and protein in CNSS tissue. Collectively, our study suggested that the UI plays an important role in locomotor activity and appetite regulation, which provides a basis for understanding the mechanism of defensive behavior and animal personality in flounder.
尿鸟素 I（UI）是促肾上腺皮质激素释放激素家族肽的成员，调节多种生理功能，包括食欲调节、防御行为和应激反应。在这项研究中，首先，我们研究了 UI mRNA 在橄榄石斑鱼（Paralichthys olivaceus）中的组织特异性分布，发现 UI mRNA 在尾部神经分泌系统（CNSS）组织中高度表达。其次，序列比对分析发现，一个保守的 cAMP 反应结合（CREB）位点和一个 TATA 元件位于 UI 基因的近端启动子中。此外， forskolin 处理激活了 cAMP-CREB 通路，并诱导培养的 CNSS 中 UI mRNA 的上调，表明 CREB 在调节 UI mRNA 表达中的作用。此外，血浆 UI 浓度和 CNSS 中的 UI mRNA 表现出明显的日节律，白天浓度较高，夜间浓度较低。第三，我们使用大胆个性（BP）和害羞个性（SP）石斑鱼作为动物模型，发现石斑鱼在夜间的运动活性明显高于白天（P<0.001），并且 BP 石斑鱼在白天和夜间的运动活性均明显高于 SP 石斑鱼（P<0.001）。对摄食行为的分析表明，BP 石斑鱼表现出更短的摄食潜伏期和更多的攻击行为。此外，qPCR 和免疫组织化学结果显示，BP 石斑鱼 CNSS 组织中 UI mRNA 和蛋白的表达水平显著降低。综上所述，我们的研究表明 UI 在运动活性和食欲调节中发挥重要作用，为理解石斑鱼防御行为和动物个性的机制提供了依据。
