FIG. 2.

CHIR-induced HSC expansion is dependent upon β-catenin. (A) c-Kit⁺ HSPCs were isolated from BM of β-catenin^−/− and WT mice. β-catenin knockout was examined by PCR assay for Δ-β-catenin. DNA from tail tissue was collected from the same mice for genotype analysis by PCR for Cre gene and β-catenin^fx/fx. (B, C) LSK-CD150⁺48⁻ HSCs were isolated from BM of WT and β-catenin^−/− mice and cultured in stem cell medium with or without 0.5 μM CHIR. Two hundred HSCs were sorted in each group by FACS. Cells were cultured for 9 days with medium change every other day. The percentages and numbers of LSK HSPCs and LSK-CD150⁺48⁻ HSCs were examined by FACS (B) and functional HSCs were evaluated by CHR assay (C). Freshly isolated (uncultured) LSK-CD150⁺48⁻ HSCs were studied as controls. Data in (B) are representative results of three independent experiments. **P < 0.01. PCR, polymerase chain reaction. Color images are available online.