Blockage of erythroid differentiation by oncogenic, but not dominant-negative, H-ras. TER119^- cells were purified as described in Figure 4 and infected with bicistronic retroviruses encoding hCD4 alone, H-ras wild-type (wt), oncogenic H-ras (H-ras.V12), or dominant-negative H-ras (H-ras.N17). Infected cells were cultured in vitro for 2 days as described in Figure 4, and the differentiation profiles were analyzed by flow cytometry. The left-hand panels show the density plots of all viable noninfected cells (hCD4^- cells), and the right-hand panels display the density plots of all viable infected cells (hCD4⁺ cells) in the same culture. The percentages of TER119^- cells (presented as total of R1 and R2 cells) and TER119⁺ cells (presented as total of R3 to R5 cells) are labeled at the bottom of each density plot.