Cell toxicity of DUX4 ΔNLS mutants.

<p>A plasmid expressing GFP was co-transfected for 48 (<i>a</i> to <i>e</i>) or 72 (<i>f</i> to <i>j</i>) hours with an empty vector (<i>a</i> and <i>f</i>) or plasmids expressing wild type DUX4 (<i>b</i> and <i>g</i>) or mutants ΔNLS1 (<i>c</i> and <i>h</i>), ΔNLS2 (<i>d</i> and <i>i</i>) and ΔNLS1-2 (<i>e</i> and <i>j</i>). About 70–80% of green fluorescent cells were observed when a plasmid expressing GFP was co-transfecetd with an empty vector (i.e. <i>a</i> and <i>f</i>). DUX4-mediated cell death, on the other hand, leaves a very low number of positive fluorescent cells (<i>b</i> and <i>g</i>) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075614#pone.0075614-Kowaljow1" target="_blank">[12]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075614#pone.0075614-Wuebbles1" target="_blank">[19]</a>. A marked reduction in toxicity was observed when using DUX4 mutants ΔNLS1, ΔNLS2 and ΔNLS1-2. For details see text and Materials and Methods section.