Fig. 1.

Inhibition of miR-133 leads to a myogenic phenotype. (A) Schematic overview of the experimental approach. Posterior somites of HH14/15 embryos were injected with FITC-labelled antagomir-133 (AM133) and the downstream analysis was performed by in situ hybridization. (B) Embryos were incubated for 6, 9, 12 and 24 h after AM133 injection as indicated. In situ hybridization detects transcripts for myogenin (Mgn, purple) and AM133 is shown in red. After 6 h, there is no change in Mgn expression in injected somites (white asterisks, n=7/8). After 9 h, the most posterior somites show a loss of (white arrowheads) or reduced (black arrowheads) Mgn expression (n=12/16). The negative effect on myogenic differentiation becomes more pronounced after 12 h and 24 h (n=8/8, n=14/14). (C) RT-qPCR for miR-133 of somites, pooled from a minimum of four embryos, injected with AM133 compared with contralateral noninjected somites, harvested after 6, 9, 12 or 24 h of incubation as indicated. ***P<0.001; **P=0.001-0.01; NS, not significant.