Knockdown of dnm2 results in motor deficits and abnormal muscle histology.(A) Quantitation of spontaneous embryo coiling at 1 dpf. On average, control morphants coiled 35.7 times in 60 seconds, while dnm2 morphants coiled only 9.5 times. (B-C) Touch-evoked swimming was measured in 3 dpf morphants. Most control and dnm2-like morphants responded to tail taps with a rapid escape response, while dnm2 morphants exhibited impaired escape responses. (D) Toluidine blue stained semi-thin sections from 3 dpf morphants. Somites from dnm2 morphants are small with highly disorganized myofibers. Scale bar is equal to 50 μm. (E) Quantification of myofiber length in 3 dpf embryos. Average myofiber size in control embryos equaled 87.8 μm, while dnm2-like morphants equaled 76.8 µm and dnm2 morphants equaled 66.0 μm (*p<0.05 ctl to dnm2-like, *p<0.01 ctl to dnm2, p = 0.056 dnm2 to dnm2-like morphants; ANOVA ). (F) Representative electron micrographs from larval dnm2 morphant muscle. Irregular membrane structures were found throughout the muscle (black arrow). Scale bar is equal to 1 μm.
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