The MYH7 deficiency causes cardiovascular defects in zebrafish. (A) Loss of MYH7 disrupts heart development. Lateral view of 3 and 5 dpf scramble gRNA injected control group and MYH7 KO larvae. Cardiac edema is clearly noticeable. Arrow at 3 dpf shows hemorrhage near heart. Edema accumulated around heart and spread to the abdominal area at 5 dpf. Arrow at 5 dpf shows enlarged heart. Scale bars: 200 μm in 3 and 5 dpf, 1 mm in middle 5 dpf. (B) The MYH7 knockout zebrafish has distorted cardiac chamber formation and looping as shown by fluorescence imaging of the Tg(actb2:hyper3) transgenic zebrafish reporter injected with scramble or MYH7 sgRNA. Representative images of control and mutant zebrafish are shown at 3, 4, and 5 dpf. Two different MYH7 KO fish at 3 dpf showed abnormal looping. Two different MYH7 KO fish at 4 dpf displayed enlarged and deformed ventricles. At 5 dpf, myh7 KO fish showed enlarged and granulated ventricle. Furthermore, a MYH7 mutant zebrafish with tubular heart is shown. Scale bars: 200 μm. (C)MYH7 is essential for proper formation of the cardiac ventricle and the pericardial cavity as shown by WMISH. Expression of MYH7, MYH7l, and mylk3 mRNAs is strongly reduced in MYH7 KO zebrafish at 4 dpf. MYH7 expression expands to the pericardial cavity and ventricular chamber in MYH7 KO fish at 5 dpf. MYH7l expression is reduced in MYH7 KO fish at 5 dpf. Expression of mylk3 in the cardiac ventricle of MYH7 KO larvae is disrupted at 5 dpf.
|
