MDA5 is a member of retinoic acid-inducible gene I (RIG-I)-like receptors (RLR receptors), which may play a crucial role in the immune regulation process. Recently, microRNAs (miRNAs) have been shown to act as an important regulator in the RLRs signaling pathway. Additionally, the MDA5 gene, as a significant cytosolic pathogen recognition receptor (PRR), its characteristics and functions have been extensively investigated, while less research has been done on the mechanisms of MDA5-miRNA mediated gene regulation. In this study, the evolution and functional characterization of MDA5 from miiuy croaker (mmiMDA5) were characterized. Comparative genomic analysis demonstrated that the ascidiacea and superclass do not have the MDA5 gene in the process of evolution. MDA5 contains four structural domains: CARD, ResIII, Helicase C, and RIG-I C-RD. The MDA5 was ubiquitously expressed in all tested miiuy croaker tissues. Moreover, the expressions were significantly up-regulated after stimulation with poly (I: C), which indicated that MDA5 might be involved in the antiviral immune response. The bioinformatics predicted programs have indicated that miR-203 has a direct negative regulatory effect on MDA5 in miiuy croaker. Furthermore, the dual-luciferase reporter assay have showed that miR-203 was the direct negative regulator of MDA5 in miiuy croaker. This study is the first to demonstrate that miRNA can suppress cytokines by regulating the RLR signaling pathway in teleost fish, providing some new ideas for studying miRNA-mediated regulation of immune responses in mammals.

MDA5是维甲酸诱导基因I（RIG-I）样受体（RLR receptors）的成员，可能在免疫调节过程中起关键作用。最近，microRNAs (miRNAs) 已被证明是 RLRs 信号通路中的重要调节因子。此外，MDA5基因作为一种重要的胞浆病原体识别受体（PRR），其特征和功能已被广泛研究，而对MDA5-miRNA介导的基因调控机制的研究较少。在这项研究中，对来自大黄鱼（mmiMDA5）的MDA5（mmiMDA5）的进化和功能表征进行了表征。比较基因组分析表明，海鞘和超纲在进化过程中没有MDA5基因。MDA5 包含四个结构域：CARD、ResIII、解旋酶 C 和 RIG-I C-RD。MDA5 在所有测试的黄鱼组织中普遍表达。此外，poly(I:C)刺激后表达明显上调，表明MDA5可能参与抗病毒免疫反应。生物信息学预测程序表明miR-203对大黄鱼MDA5具有直接的负调控作用。此外，双荧光素酶报告基因分析表明，miR-203是大黄鱼MDA5的直接负调节因子。本研究首次证明miRNA可以通过调控硬骨鱼体内RLR信号通路抑制细胞因子，为研究miRNA介导的哺乳动物免疫反应调控提供了一些新思路。poly(I:C)刺激后表达显着上调，表明MDA5可能参与抗病毒免疫反应。生物信息学预测程序表明miR-203对大黄鱼MDA5具有直接的负调控作用。此外，双荧光素酶报告基因分析表明，miR-203是大黄鱼MDA5的直接负调节因子。本研究首次证明miRNA可以通过调控硬骨鱼体内RLR信号通路抑制细胞因子，为研究miRNA介导的哺乳动物免疫反应调控提供了一些新思路。poly(I:C)刺激后表达显着上调，表明MDA5可能参与抗病毒免疫反应。生物信息学预测程序表明miR-203对大黄鱼MDA5具有直接的负调控作用。此外，双荧光素酶报告基因分析表明，miR-203是大黄鱼MDA5的直接负调节因子。本研究首次证明miRNA可以通过调控硬骨鱼体内RLR信号通路抑制细胞因子，为研究miRNA介导的哺乳动物免疫反应调控提供了一些新思路。生物信息学预测程序表明miR-203对大黄鱼MDA5具有直接的负调控作用。此外，双荧光素酶报告基因分析表明，miR-203是大黄鱼MDA5的直接负调节因子。本研究首次证明miRNA可以通过调控硬骨鱼体内RLR信号通路抑制细胞因子，为研究miRNA介导的哺乳动物免疫反应调控提供了一些新思路。生物信息学预测程序表明miR-203对大黄鱼MDA5具有直接的负调控作用。此外，双荧光素酶报告基因分析表明，miR-203是大黄鱼MDA5的直接负调节因子。本研究首次证明miRNA可以通过调控硬骨鱼体内RLR信号通路抑制细胞因子，为研究miRNA介导的哺乳动物免疫反应调控提供了一些新思路。