Fig. 3

Targeted knockdown of zdlst phenocopies the ste^−/− mutant phenotype. a, b Knockdown of zdlst by injection of Morpholino-modified antisense oligonucleotides (MO-DLSTsplice) (a) phenocopies the ste mutant phenotype (b), whereas injection of the same amount of standard control Morpholino (MO-control) (c) does not impact on heart rate. d Similar to ste^−/− mutants, heart rate of DLSTsplice morphants is significantly reduced compared to MO-control-injected embryos at 72 hpf. e, f Transmission electron microscopy (TEM) of wild-type and ste^−/− ventricular myocardium at 72 hpf. Scale bar represents 3 µM. e In wild-type myocardium, mitochondria display regular structure of inner and outer membrane and cristae. f In ste^−/− myocardium, mitochondria display derangement of structure with severely reduced numbers of cristae. g, h TEM of wild-type and ste^−/− skeletal muscle at 72 hpf. Scale bar represents 1 µM. g In wild-type skeletal muscle mitochondria exhibit regular morphology. h In ste^−/− skeletal muscle mitochondria are characterized by large vacuoles and reduced numbers of cristae