LAUSR

ABSTRACT MicroRNA‐122 (miR‐122) was originally identified in mouse and then lots of researches on miR‐122 had been performed in mammals. However, the functional study of miR‐122 were restricted in fish. In miiuy croaker, miR‐122 is sensitive to poly(I:C) stimulation. In this study, a combination of bioinformatics and experimental techniques were used to investigate the functions of miR‐122. DAK is a putative target gene of miR‐122 which was predicted by bioinformatics, and further the luciferase reporter assays were used to confirm the target sites in DAK 3'untranslated region. The inhibiting effect of miR‐122 mimics or pre‐miR‐122 on DAK presented the dose and time dependent manners, and the pre‐miR‐122 showed stronger inhibiting effect on DAK than the miR‐122 mimics. Therefore, the miR‐122 participate in regulating RIG‐I‐like receptors signaling pathway via inhibiting DAK which is the inhibitors of MDA5. The expression of miR‐122 and DAK showed negative relationship in both miiuy croaker spleen and macrophages, which imply that miR‐122 may regulate DAK at the post‐transcriptional level. These results will enhance our understanding about the regulation of miRNAs on immune response in fish. HighlightsmiR‐122 could response to poly(I:C) stimulation in miiuy croaker.Miiuy croaker DAK is a putative target of miR‐122.Expression profiles of miR‐122 and DAK were conducted in vitro and vivo.