The role of miR-92 in regulating early development and metamorphosis of Japanese flounder Paralichthys olivaceus.

MicroRNAs are a class of short non-coding RNAs that contain approximately 22 nucleotides and play a regulatory role in RNA silencing and translational repression. miR-92 belongs to the miR-17-92 family and has a regulatory effect on cell proliferation, apoptosis, and expression of proto-oncogenes and tumor suppressor genes. However, its function in flatfish is unclear. In this study, we used farmed Japanese flounder, Paralichthys olivaceus, and showed that gata5 is a target gene of miR-92. Experiments on miR-92 overexpression indicated that gata5 and sox17 were downregulated, while the transcription level of ntl increased. By contrast, depletion of miR-92 resulted in increased gata5 and sox17 levels and reduced ntl level. Moreover, thiourea treatment indicated that miR-92 may inhibit the metamorphic development of Japanese flounder. Our study suggests that miR-92 regulates the fate of endoderm and mesoderm by controlling gata5.