Defects in body and inner ear morphology in zebrafish morphant embryos. MMOs against specific miRNAs were injected to 1-celled embryos and the phenotype 55 h later is presented. A "standard" morpholino (MO Stnd) with a sequence that is not expected to target any known zebrafish RNA served as a negative control for unspecific toxicity. (A) Body phenotypes shown at low magnification.Arange of body types was apparent in miR-15a-1 morphants, including complete tail truncation as the most severe outcome (panel MMO-15a-1). miR-18a morphants had normal bodies (panel MMo-18a), except when MOs were used at very high doses (data not shown). (Scale bar, 500 μm.) (B) Higher power views of the inner ears from the same embryos as those shown on column (A), photographed with Normarski optics. These are the same images shown in Fig. 4. (Scale bar, 100μm.) (C–E) Defects in the sensory organs and ganglia of the inner ears from miR-morphant zebrafish. Confocal image slices were obtained from lateral views of the inner ear and were collapsed as Z-projections to view hair cells (labeled with HCS-1 antibody; column C) and neurons (labeled with HuC antibody; column D) associated with the inner ear. Column (E) presents merged photos. Embryos injected with standard MO showed the normal distribution of 2 maculae, 3 cristae, and a comma-shaped statoacoustic ganglion (SAG). Unlabeled hair cell clusters are cranial neuromasts. 15a-1 morphants had smaller maculae and were missing the 3 cristae. 18a morphants had smaller maculae (notice the utricular macula assumes a curved distribution of hair cells). Abbreviations: AC, anterior crista; LC, lateral crista; PC, posterior crista; SAG, statoacoustic ganglion; SM, saccular macula; UM, utricular macula. (Scale bar, 30 μm.)
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