Fig. 4

Overexpression of miR-125c results in severe abnormalities and reduction of motility during embryonic development. (A) miR-125c injection induces distinct embryonic malformation in a dose dependent manner during early development (24–96 hpf). Injection of miR-125c mimics together with inhibitor was performed to determine whether knockdown of miR-125c can rescue the morphological defects. Scale bars, 0.2 mm. (B) miR-125c injected embryos exhibit diminished swimming ability in response to mechanosensory stimulation at 3 dpf. a-c) Touching the tail provokes the wild-type embryos to swim away rapidly (within 120- 240 ms) (n = 5). d-f) But, miR-125c injected embryos swim slowly in circular motions (n = 5). (C, D) Histological analysis of the eye in miR-125c injected embryos at 4 dpf reveals smaller lens and thinner inner plexiform layer (IPL). Scale bars, 20 μm. (E, F) Magnified views shows clumped and disorganized cells in the inner nuclear layers (INL) in miR-125c injected embryos. (G, H) Smaller brain is observed in miR-125c injected embryos at 4 dpf. Scale bars, 40 μm. (I, J) Magnified views reveals tightly clumped cells with reduced extracellular space in the miR-125c injected embryos. (K, L) miR-125c injected embryos at 4 dpf exhibit smaller myotome and degenerated muscle fibers. Scale bars, 40 μm.