Fig. 3

Transient manipulation of miR-137 activity. (a) Design of morpholinos (MO) targeting the three dre-pre-miR137 copies, with mature miR-137 highlighted in yellow. Alignment was performed using CLUSTAL 2.1. (b) (i) Morphology of 72 hpf zebrafish embryos injected with MOs. (b) (ii) Morphology of 72 hpf zebrafish embryos injected with synthetic miRNAs. (c-h) Percentage of dead, malformed and normal embryos at 28 hpf following injections of MOs and synthetics miRNAs. MO137-02, MO-Control and miR-control injections were well-tolerated, while MO137-01 and miR137-mimics injections induced strong morphological defects that were most likely due to off-specific effect (see Results). These malformations included, but were not limited to, (1) heart edema, (2) curved tail and (3) abnormal trunk curvature. Percentage of normal embryos is presented in white, abnormal in light gray and dead in dark grey. (i-j) In situ hybridization against dre-miR137 at 3 dpf showing that 8 ng of MO137-02 inhibits endogenous miR-137 expression in zebrafish to a threshold that is no longer detectable even after extended revelation. miR, miRNA.