Akt-deficient progenitors generate marrow B-lineage precursors. (A) Representative flow cytometric analysis of BM cells from chimeras established with Akt1^+/+Akt2^+/− (top) or Akt1^−/−Akt2^−/− (bottom) progenitors 12 to 14 weeks previously. The left-most plots are gated on viable donor-derived (DAPI⁻ Ly5^B6+) cells. Numbers in plots indicate the frequency of events in the indicated gate as a function of the indicated parent population. Pro-B, CD43⁺ B220⁺ CD19⁺ AA4⁺; pre-B, CD43^low B220⁺ IgM⁻ AA4⁺; immature B, CD43⁻ B220⁺ IgM⁺ AA4⁺; mature B, CD43⁻ B220⁺ IgM⁺ AA4⁻. (B) Absolute cell numbers for respective BM populations were calculated using the gates shown in panel A. Error bars indicate the SEM for each group; n = 5. Data are representative of 2 separate experiments. *P ≤ .01.