Cilia in scohi459 mutant embryos. (A,B) Confocal projections showing the pronephric duct in a wild-type embryo (A) and an arl13b morphant (B) at the 20-somite stage, stained with anti-acetylated tubulin (red) and anti-Sco (green). Signal in B is overexposed. Scale bars: 5 μm. (C,D) Confocal projections showing cilia defect (stained with anti-acetylated tubulin, red) in the pronephric duct (stained with anti-Cdh17, green) in a scohi459 mutant embryo (D), compared with a wild-type sibling (C), at 33 hpf. Scale bars: 10 μm. (E,F) Confocal projection showing cilia (stained with anti-acetylated tubulin, red) in the pronephric duct (stained with anti-Cdh17, green) in embryos at 5 dpf. Scale bar: 20 μm. (G,H) Electron micrographs showing the ultrastructure of cilia in the scohi459 mutant at 5 dpf. H shows an enlarged cross section; red arrowhead indicates a dynein arm. Scale bars: 1 μm in G; 100 nm in H. (I) Cilia motility in scohi459 mutant and wild-type siblings at 5 dpf. Cilia with a beating frequency of between 36 and 55 Hz are categorized as fast, whereas cilia with frequency of between 21 and 35, and between 5 and 20 are categorized as medium and slow, respectively. mph, morphant; mut, mutant; wt, wild type.