Fibronectin-null cells assemble exogenous fibronectin when adherent to 160/180 kDa fragments or “fingerless” fibronectin, but not when adherent to 7F3-14F3 or smaller type III-module containing proteins.
Fibronectin-null cells in DMEM containing 0.2% BSA and 9 µg/ml RX-fibronectin were incubated at 37°C for 4 hr on cover slips coated with fibronectin, 7F3-10F3, 12F3-14F3, 7F3-14F3, 160/180-kDa fragments (160/180 kDa), or “fingerless” Fibronectin; at 3 µg/ml. Cells were fixed with paraformaldehyde and observed under the fluorescence microscope. The result is representative of 3 sets of experiments. Bar = 20 µm.