Fig. 6. Neural tube-dependent vascular plexus formation in presomitic mesoderm explants. Flt1^+/– mouse presomitic mesoderm grafts (PSM) (8.5 dpc) were co-cultured with HH10-13 stage quail neural tubes (NT) or notochords (NC) in collagen gels for 72 hours. Individual co-cultures were photographed at 0 (A,D), 24 (B,E) or 48 hours (C,F) to demonstrate the growth of the tissues. The same cultures were then fixed at 72 hours and stained for ß-gal (G,H). The purple arrows indicate the respective tissues and the black arrows indicate the vascular plexus that forms in PSM/NT co-cultures. The arrowheads indicate the few ß-gal positive presumptive vascular cells seen in PSM/NC co-cultures. n>10 for PSM/NT co-cultures and n=3 for PSM/NC co-cultures. Scale bars: 350 µm in A-F; 140 µm in G,H.