Fig. 4

Figure 4. Type IV collagens are expressed in the zebrafish glomerulus. (a) Schematic (created with Biorender) showing the 3 type IV collagen alpha chains expressed in the glomerular basement membrane (α3, α4, and α5) on the left, and their interaction to form the α4α4α5(IV) heterotrimer on the right. (b) In situ hybridizations showing the expression patterns of all 6 type IV collagen chains in zebrafish at 4 days post fertilization (dpf). The panels on the left are lateral views of the whole embryo (anterior left, Bar = 100 μm). The panels on the right are dorsal views of the head and anterior trunk region (anterior to the left, Bar = 50 μm). The inlet panels in the col4a1 and col4a3 whole embryo profiles show the glomerulus in the transverse section (Bar = 10 μm) through the point in the embryo highlighted in a red-dashed line on the whole embryo image. (c) Transverse sections through the glomerulus of 4 dpf zebrafish embryos immunostained for podocin (left panel) and pan-collagen IV (middle panel). The right panel shows schematic representation of the tissues in the cross-section at this position. DA, dorsal aorta; Glom, glomerulus; Not, notochord; PT, proximal tubule; Som, somite. To optimize viewing of this image, please see the online version of this article at www.kidney-international.org.