Figure 4.

Relationship between cell-surface Fas expression and BrdU incorporation at different stages of cell cycle or apoptosis (PI incorporation) in adherent primary precursors. (A,B) Representative frequency histogram of PI incorporation (A) and scatter-plot of combined PI incorporation and Fas immunofluorescence (B) indicates the thresholds for the separate analysis of BrdU content in neuroblasts at S/G2/M (pink), G0 (green), or apoptosis (red). (C-F) Representative scatter-plots of the overall positive relationship between Fas expression and BrdU incorporation (C) and separated by cell-phase, S/G2/M (D), G0 (E) and apoptosis (F). Arrows in S/G2/M condition (D) indicate a group of cells that exhibited the highest levels of BrdU incorporation (suggesting recent completion of S-phase) and cell-surface Fas expression. Insets in figures D,E and F indicate Pearson's product moment correlations (obtained by averaging intensities across 6 independent samples). Asterisks indicate that the correlation was statistically significant with a 2-tailed test. These data indicate that the correlation between BrdU incorporation and cell-surface Fas expression is higher during cell cycle and G0 as compared to apoptosis.