Northern blot confirmation of VEGF-responsive genes. ECs were cultured in 3D collagen matrices with (+) or without (-) VEGF165. After 24 hours, total RNA was isolated and analyzed by Northern blot, as described in the "Methods". The 32P-radiolabelled probes used and their corresponding GenBank accession numbers are indicated, and abbreviated gene names are given in perentheses (also see Table I). The GAPDH probe was included as a control for the integrity and loading of the total RNA. Blots are representative of those obtained in two or three separate experiments, with similar results.