Fig. 4

Fig. 4

Collagen IV Interacts Genetically with, and Directly Binds to, Slit(A and B) Projections of confocal images of BGUG-labeled RGC axons in a WT (A) and a double-heterozygous carrier of drg^s510 and ast^ti272z (B) at 6 dpf. Arrows point at axons that trespass the laminae.(C) Quantification of RGC axon targeting defects.(D–F) Analysis of Col IV, Slit1 and Agrin interactions using solid-phase ELISA binding assays (n = 3, with duplicate samples in each experiment). Agrin and Slit1 bind Col IV via protein-protein interactions (HS independent, not inhibited by exogenous heparin), and Agrin binds Slit1 via its HS-GAG chains (marked reduction in presence of heparin).(G) Analysis of Col IV ligand binding to Slit1 using surface plasmon resonance. Col IV binds to Slit1 in a dose-dependent fashion, with K_D = 0.65 nM.Error bars represent the SEM. See also Figure S3.