Influence of DAPT inhibition of Notch signaling on differentiation of CD34⁺ CB cells in hybrid human-mouse FTOC. Murine fetal thymic lobes were seeded with human CD34⁺ CB cells and cultured in FTOC for 28 days in the absence of presence of 2, 5, or 10 μM DAPT. (A) Frequencies of subpopulations of human hematopoietic cells at the end of the culture period. Bars represent mean ± SEM of 4 independent experiments. Asterisks indicate statistically significant differences (P < .05) compared with vehicle-treated control. (B) Representative dot plots and histogram of flow cytometric analysis of control cultures and cultures treated with 10 μM DAPT. Bold line and thin line in the histogram represent results from the DAPT-treated and control culture, respectively.