Actin and myosin staining of isolated hearts shows myofibrillar reorganization in <i>seizure</i> mutants.

<p><b>(A)</b> Z stacks from <i>in situ</i> hearts (1 week old) stained with phalloidin to show actin filaments (green). Both <i>Wt</i>^<i>CS</i> and <i>KCNQ</i>^<i>370</i> mutant hearts show distinct circumferential myofibrils that are tightly packed. <i>Sei</i> mutant hearts show gaps between myofibrils that are disorganized (double headed arrows indicate comparable chambers of the heart). In addition, valve structures appear to be compromised (arrow heads). <b>(B)</b> Higher magnification of one chamber of the heart (abdominal segment 4) stained for actin (green) and myosin (red). Myofibrils in the heart from a 3 week old <i>Wt</i>^<i>CS</i> fly (top) are circumferentially organized and tightly packed; the same region from a 3 week old <i>sei</i>^<i>ts1</i> mutant heart (bottom) that shows severe myofibrillar disarray and obvious gaps.