Specificity of phenotype observed upon knock down of Mef2c.

<p><b>A. </b><i>mef2c</i>γ- and <i>mef2c</i>γ+ isoforms are expressed on RNA level in heart tissue enriched explants at stages 24, 28, and 32 as revealed by qPCR. Expression is shown relative to <i>gapdh</i>. <b>B.</b> mMef2cγ- and mMef2cγ+ are expressed on protein level upon RNA injection into <i>Xenopus</i> embryo at comparable levels. β-Tubulin served as loading control. Note that the Mef2c antibody used does not recognize endogenous <i>Xenopus</i> Mef2c protein. The asterisk indicates unspecific background. <b>C–F.</b> Mef2c MO was unilaterally injected together with <i>GFP</i>, <i>mMef2c</i>γ+ <i>or mMef2</i>γ- RNA as indicated. <b><i>C, E</i></b> Expression of the cardiac marker genes <i>myh6</i> and <i>tnni3</i> was monitored at stage 20 or stage 28. Black arrowheads indicate reduced marker gene expression, white arrowheads highlight the rescued situation. Ventral views of embryos are shown. <b>D, F.</b> Quantitative presentations are shown. N: number of examined embryos; n: number of independent experiments; st: stage; **, <i>p</i>≤0.01.