VEGF induced capillary morphogenesis of endothelial cells and dot blot screening. HUVECs (3 × 105 cells/ml) were grown human recombinant VEGF165 (100 ng/ml), as described in Experimental Procedures. (A) Elongation and morphogenic changes of ECs after 8 hr exposure to VEGF; (B) ECs formed a mosaic of interconnecting networks after 16 hr of exposure to VEGF; (C) High resolution phase contrast phomicrograph of interconnected ECs developing vacuoles after 24 hr exposure to VEGF, as indicated by white arrowheads; and (D) cross section of an eosin-stained fixed gel, reveals the formation of capillary-like structures after 36 hr exposure to VEGF (indicated by black arrowheads). White arrows indicate cell-contacts. Magnification 100X. Bar, 50 μM. E, F) Escherichia coli cultures transformed with plasmids containing enriched cDNAs, were spotted from a 96-well dish onto duplicate nylon membranes. The membranes were hybridized with (E) forward-subtracted and (F) reverse-subtracted cDNA 32P-radiolabeled probes, as described in the "Methods". Black arrows indicate common genes detected by both probes.