Figure 1

Ultrastructural analysis of the glomerular basement membrane. Mice deficient in (a-c) integrin α2 (ITGA2), (d-f) discoidin domain receptor (DDR)1 and (g-i) collagen (IV) α3 (COL4A3), and (j-l) wildtype controls. Electron microscopy demonstrates a localized, mushroom-like isodense thickening of the glomerular basement membrane (GBM) in (a-c) ITGA2-deficient mice, compared with (j-l) wild-type mice. (b, c) These characteristic subepithelial bulges (white arrows) seem to be identical to those observed in (d-f) DDR1 knockouts [19]) (g-i) By contrast, splitting and thickening of the GBM and fibrillar collagens indicating fibrosis were found in COL4A3-deficent mice. Original magnification: (a, d, g, j) × 3,000 to 7,000; (b, c, e, f, h, i, k, l) × 15,000 to 30,000. U = urinary space; C = capillary lumen.