Fig. 6. Interference with collagen type IV synthesis and secretion blocks capillary morphogenesis in 3D collagen matrices. EC cultures were treated with or without ethyl 3,4-dihydroxybenzoate (edb), an inhibitor of prolyl hydoxylase. Cultures were fixed at varying times, stained, quantitated for lumen formation (B) and photographed (A). Bar, 50 µm (A). Cell extract samples (from cultures with or without edb at 300 µM) and at different times of culture were collected and run on 7% SDS-PAGE gels (C). Lanes 1 and 2, 0 hours; lanes 3,4, 8 hours; lanes 5,6, 24 hours; lanes 7,8, 48 hours; lanes 9,10, 72 hours. Proteins were blotted to PVDF membranes and were probed with antibodies to collagen type IV. Arrows indicate the position of the 1 and 2 chains of collagen type IV.