Maintenance of hematopoiesis in the combined absence of β- and γ-catenin. (A) γ-Catenin expression in embryonic day 12.5 fetal liver cells of the indicated genotypes as detected by immunoblot analysis with mAbs specific for the carboxy terminus of γ-catenin (clone 15) and tubulin (to ensure equal protein loading). Numbers indicate the molecular weight in kDa. (B) Genomic DNA from the indicated types of primary chimeras was isolated 10 days after pI-pC injection from sorted CD45.2⁺ BM cells and subjected to PCR analysis to detect Mx-Cre, γ-catenin, and β-catenin alleles. The mutant (indicated as null) and wild-type (wt) γ-catenin alleles are detected as 150 bp and 300 bp PCR products, respectively. The floxed (indicated as lox) and deleted (Δ) β-catenin alleles yield 183 bp and 481 bp bands, respectively. (C) β-Catenin was deleted in primary recipients by pI-pC. After 10 to 14 days, a mixture of deleted (CD45.2) and wild-type (CD45.1) BM cells were transplanted into lethally irradiated secondary recipients (CD45.1). Recipient mice were bled at the indicated time points. Each point represents the mean percentage of CD45.2⁺ peripheral blood lymphocyte (± SD) of 4-5 recipient mice per individual fetus. Each curve represents an individual donor fetus. (D) Histograms depict the contribution of CD45.2⁺ BM precursors to the lymphoid (B and T cells) and myeloid lineages (neutrophiles, CD11b⁺ GR1⁺, and monocytes CD11b⁺ GR1⁻) at 16 weeks after reconstitution. Numbers on the graphs are percentage of total cells in delineated regions. Data show a representative analysis (of 5-7 performed).