Figure 3.

Spreading of U251 transfectants. Spreading of wild-type transfectants (U251NG2.51, a–c) and chimeric transfectants (U251NG2/CNTN.40, d–f, and U251NG2/L1.7, g–i) was compared on surfaces coated with PLL, mAb β1, and mAb D120. Spreading was stopped after 1 h by fixation with 2% paraformaldehyde, and cells were stained with a polyspecific antiserum raised against whole U251 cells. Each of the three cell populations exhibited good spreading on PLL and mAb β1, but only the wild-type transfectants spread effectively on mAb D120. Similar results were obtained with independently derived clones of each cell type (U251NG2.35, U251NG2/CNTN.10, and U251NG2/L1.3). In j–l, cytochalasin D (10⁻⁶ M) was used to inhibit spreading of the wild-type transfectants on each of the three surfaces. Bar in a, 50 μm.