Blocking the translation of dnm mRNA in zebrafish embryos causes proteinuria. Wild‐type zebrafish embryos were injected with an anti‐dnm morpholino or a scrambled control morpholino, followed by a mixture of 3 and 70 kDa dextran molecules. (A, B) Representative fluorescence images of the proximal tubule epithelial cells (circled structure) in a dynamin‐knockdown zebrafish embryo. (C, D) The number of fluorescent droplets below the luminal surface was counted in control embryos, dynamin‐knockdown embryos, and wild‐type embryos injected with puromycin aminonucleoside (PAN) as a positive control for increased glomerular permeability. *p < 0.05 versus control. A digital high‐pass filter has been placed over panels A and B to enhance the contrast between reabsorption droplets and the surrounding tissue. The images in A and B were taken at the same magnification. Scale bar = 10 μm.