Fig. 4. Quantitation of retraction fiber formation. (A) Using cultures like those described in Fig. 3, we examined at least 200 cells to determine the percentage of cells that displayed retraction fibers, as determined by staining with the poly-specific rabbit antibody against B28 cells. The figure compares parental B28 cells (P) and B28 cells transfected with wild-type NG2 (clone 6), NG2/S1342A (clones 42 and c44), NG2/S999A (clones 51 and c65), NG2/L1 (clone 5) and NG2/CNTN (clone M). Mean and standard error values were calculated from data obtained with three replicate plates of each cell type. (B) Using the same sets of cells described in A, we counted the number of retraction fibers per cell. Values for at least 13 cells are plotted for each cell type in the figure. Horizontal bars show the mean value for each cell type. Cells with small numbers of retraction fibers are the same ones identified as low responders in A.
