Osteoblastoid-specific depletion of Smo impairs reappearance of early B-lymphoid progenitors after BM ablation. (A) BM ablation protocol. Mice were injected intraperitoneally with 5-FU, and BM was collected as indicated. (B-D) Pre-/pro-B (B220^loCD19⁻CD43⁺), pro-B (B220^loCD19⁺CD43⁺), and pre-B (B220^loCD19⁺CD43⁻) compartments in mice of the indicated genotypes were examined 7 days (B), 14 days (C) and 21 days (D) after 5-FU treatment. The number of mice in each group is indicated in the insets (parentheses). Significant differences were determined by the Kruskal-Wallis test. (E) BM myeloid cells (Mac1⁺Gr1⁺) were assessed 7, 14, and 28 days after 5-FU treatment in the same mice. The number of mice in each group is indicated in the insets of panels B-D (parentheses). Significant differences were determined as in B-D. (F) The percentages of Rag1⁺ (left) and Rag1⁺B220⁻ (ELPs/CLPs) (middle) BM cells 7 days after 5-FU treatment were determined in mice of genotypes indicated at right. The number of mice in each group is indicated in the insets (parentheses). Pre-/pro-B (B220^loCD19⁻CD43⁺), pro-B (B220^loCD19⁺CD43⁺), and pre-B cell (B220^loCD19⁺CD43⁻) compartments were also examined 7 days after ablation (right). Mean and SD are indicated. Significant differences were determined as in panels B-D.