Extracellular Matrix/metabolism; Morphogenesis; Retina/growth & development; Retinal Vessels/physiology; Adaptor Proteins, Signal Transducing; Animals; Calcium-Binding Proteins; Endothelial Cells/cytology; Endothelial Cells/metabolism; Endothelial Cells/physiology; Extracellular Matrix/genetics; Fibronectins/genetics; Fibronectins/metabolism; Integrin alpha Chains/genetics; Integrin alpha Chains/metabolism; Intracellular Signaling Peptides and Proteins/genetics; Intracellular Signaling Peptides and Proteins/metabolism; Membrane Proteins/genetics; Membrane Proteins/metabolism; Mice; Mice, Knockout; Phosphorylation; Pseudopodia/genetics; Pseudopodia/metabolism; Pseudopodia/physiology; Receptors, Notch/genetics; Receptors, Notch/metabolism; Retina/cytology; Retina/metabolism; Retinal Vessels/embryology; Retinal Vessels/metabolism; Signal Transduction; Vascular Endothelial Growth Factor A/genetics; Vascular Endothelial Growth Factor A/metabolism; Vascular Endothelial Growth Factor Receptor-2/genetics; Vascular Endothelial Growth Factor Receptor-2/metabolism