Bmi1 augments proliferation and maintains clonogenicity of Scl/p210 cells. (A) Representative fluorescence photographs showing CFU-Cs of Ntg;Mk-, Ntg;Bmi1-, Scl/p210;Mk-, and Scl/p210;Bmi1-expressing cells during serial replating on methylcellulose in vitro. Earlier, Bmi1 was subcloned into Sfβ91-IRES-RFP retroviral vector. HSC/Ps were transduced and RFP⁺ cells were sorted by flow cytometry (FACSAria II; BD Biosciences). (B) Frequency of CFU-Cs in the BM of Ntg;Mk-, Ntg;Bmi1-, Scl/p210;Mk-, and Scl/p210;Bmi1-expressing cells during serial replating on methylcellulose in vitro. (C) Cumulative cell number expansion of Ntg;Mk-, Ntg;Bmi1-, Scl/p210;Mk-, and Scl/p210;Bmi1-expressing cells grown in IMDM-based liquid culture supplemented with 10% FCS, 100 ng/mL of SCF, 100 ng/mL of thrombopoietin, and 100 ng/mL of G-CSF. Data represent 1 of 2 independent experiments with similar results. (D) CFU-C content (expansion) per culture of sorted RFP⁺ BM cells from Ntg;Mk-, Ntg;Bmi1-, Scl/p210;Mk-, and Scl/p210;Bmi1-expressing groups during liquid culture in respective time points in vitro. The CFU-C assay was performed in triplicate. Data represent 1 of 2 independent experiments with similar results. Microphotographs were obtained with a DC Imaging microscope, model BA310, with a ×20 objective (OM, ×200). The images were acquired with a Moticam 2500 color camera (5.0 MPixal, USB2.0), Motich China Group Co Ltd, and processed using Motich Image Plus 2.0 software.