V-ATPase loss of function alters pH and induces autophagy defects in neuromasts. (A) Lysotracker staining in a wild-type neuromast at 4 dpf was reduced in atp6v1f−/− mutants. Neuromast cells are marked by Tg(cldnb:lynEGFP) transgene expression. Arrowheads point out basal accumulation of Lysotracker in wild-type hair cells. Scale bars: 5 µm. (B) Wild-type and atp6v1f−/− mutant neuromasts at 4 dpf stained for Lc3b-GFP (green) and nuclei using DAPI (blue). Arrowheads point out Lc3b-GFP aggregates. White and black dashed line circles indicate the neuromast boundary. (C) Quantification of volume of individual Lc3b-GFP aggregates in neuromasts from wild-type and atp6v1f−/− embryos. The number of data points reflects the finding that each embryo can have multiple neuromast aggregates. n=number of embryos. ***P=0.0005 and ****P<0.0001 by unpaired Student's t-test with Welch's correction. (D) Anti-Lamp1 antibody staining shows colocalization with Lc3b-GFP aggregates in atp6v1f−/− mutant neuromast. Yellow dashed line circles indicate hair cell cluster within a neuromast.
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