Fig. 6

Knockdown of Dnmt1 disrupts the normal development of semicircular canals and otolith organs. A, Knockdown of Dnmt1 fails to form normal semicircular canals as well as otolith organs from 48 hpf to 96 hpf. Anterior, posterior and lateral (ventral) semicircular canals together with two otolith organs are well-structured in controls and in the mRNA rescue larvae, while in Dnmt1-MO morphants the normal semicircular canals are absent and the malformation of otolith maintain from 48 to 96 hpf. B, The inner ear structure of zebrafish at 48 hpf in white light in controls shows two normal otolith organs labelled as the anterior utricle and the posterior saccule, and upsides epithelial thickening. Multiple abnormal otolith phenotypes after Dnmt1 depletion are found at 48 hpf: increased number malformation, decreased number malformation and two abnormal otoliths. Successful rescue of phenotypic abnormalities is found in Dnmt1-MO + Dnmt1 mRNA groups. C, Different types of deformities and their percentages are compared among the three groups (n = 62, 420 and 81 in controls, Dnmt1-MO morphants and rescue embryos respectively). u: utricle, s: saccule, ap: anterior protrusion, ab: anterior bulge, vb: ventral bulge, vp: ventral protrusion, pb: posterior bulge and pp: posterior protrusion. Red arrow heads show the abnormal fusion of anterior and posterior protrusions. All images are lateral views with the anterior to the left and the dorsal side up. Scale bars are 50 μm (A, B)