FIG 2.

Cell-autonomous reversal of the B-1 progenitors to pre-proB cell ratio in Rybp-deficient bone marrow. (A) Representative flow cytometry plots of total bone marrow cells or of Lin⁻/B cells (lineage-depleted cells, except for B220) labeled with antibodies against B220 and CD19 markers. (B) Relative size of B-cell subpopulations (gated as indicated in the corresponding plots) from control (Rybp^f/f) and mutant (Rybp^Δ/Δ) Lin⁻/B220 cells. (C) Absolute and relative cell numbers of B220^−/lo CD19⁺ and B220⁺ CD19⁻ subsets within Lin⁻ CD19⁺ (left) or Lin⁻ B220⁺ (right) populations in mice of the indicated genotypes. (D) Increased cell numbers of mutant B1 progenitors (Lin⁻ AA4.1⁺ B220^−/lo CD19⁺ ckit⁺). (E) B220/CD19-labeled cells in newborn and mice at day 3. Bar graphs show means and SD of relative contents in Lin⁻ CD19⁺ B220^−/lo and Lin⁻ CD19⁻ B220^med populations of six pups/experiment from two independent experiments. (F, left) Schematic representation of hematopoietic transplantation of 5 × 10⁶ total bone marrow CD45.2⁺ Rybp^f/f Cre⁻ or Cre⁺ cells into lethally irradiated CD45.1⁺ mice; 4 weeks later, hosts in which ≥90% of circulating cells were CD45.2⁺ were treated with poly(I·C) and sacrificed for analysis 4 weeks later. (Right) Representative plot of B220/CD19-labeled cells. (G) Absolute number of donor B220^−/lo CD19⁺ and B220⁺ CD19⁻ compartments containing B1 progenitors and pre-proB cells, respectively, of the indicated genotypes. Data are from two independent experiments (n = 6 and n = 4 for each genotype in transplants 1 and 2, respectively). Bar graphs show mean values and SD. In panels B and C, ten mice were analyzed of each genotype. **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001; n.s., not statistically significant (P ≥ 0.05).