Fig. 6.

Accumulation of filtered vitamin D-binding protein (DBP) coupled to enhanced green fluorescent protein (EGFP) (DBP-EGFP) in the pronephric tubular epithelium after zApol1 knockdown. Transparent CADE zebrafish larvae (4 dpf), expressing DBP-EGFP in the circulation, were injected with Alexa fluor 647-conjugated 10-kDa dextran at 3 dpf to visualize the pronephric tubular epithelium (outlined in blue) due to uptake of the filtered dextran. DBP-EGFP was absent from the tubular epithelium in control and zMyh9 knockdown larvae. In contrast, DBP-EGFP was present in the tubular epithelium of zApol1 knockdown larvae, indicating leakage of DBP-EGFP through the glomerular filtration barrier. Note that knockdowns did not affect the morphology of tubules, which were imaged in vivo in somewhat differently orientated larvae. Scale bar = 50 μm.