mpp5am520 mutants and tnnt2a-ATG morphants display a similar structural disorganization of pronephric glomerulus. A: In 4-dpf wild-type embryos, the pronephric glomerulus contains several glomerular capillaries together with mesangium, which is arborized in shape. Podocytes and GBM cover the glomerular capillaries and mesangium en bloc. In both 4-dpf mpp5am520 mutants (B) and tnnt2a-ATG morphants (C), the extremely dilated dorsal aorta (DA) lies between a pair of glomerular primordia, which do not contain any fine glomerular capillaries or mesangium. NC, notochord. Scale bar = 500 nm.