Reintroduction of C/EBPα in AML CD34⁺ cells. (A) Schematic overview of the lentiviral overexpression vectors used in these studies. (B) Western blot analysis of C/EBPα-ER in CD34⁺ CB stem/progenitor cells. (C) Transduction efficiency of CD34⁺ AML cells. (D) Phase-contrast and Venus fluorescence (GFP channel) pictures indicating the presence of Venus⁺ CAs (circled) in week 2 leukemic MS5 cocultures. See “Materials and methods; Microscopy and cytospins.” (E) DNA-binding experiment to C/EBPα-specific probe with nuclear extracts of 50 000 CD34⁺ AML cells from MS5 cocultures treated for 1 week with or without 500 nM 4-OHT. (F) Q-PCR for the C/EBPα target gene G-CSF-R after 1 week of coculture on MS5 in the presence of 500 nM 4-OHT. mRNA levels were normalized against GAPDH mRNA levels and C/EBPα-transduced values are shown relative to control Venus-transduced values. An average of 2 samples is shown with SEM.