NFI-A knockdown impairs erythroid (E) differentiation of HPCs. (A) Growth curve of HPCs in unilineage E culture infected with control vector or siNFI-A (mean ± SEM values of 3 independent experiments). (B) The histogram shows the percentage of viable (or 7-amino-actinomycin D-negative) cells detected by flow cytometry (representative of 3). (C) Western blot analysis confirming NFI-A knockdown in siNFI-A expressing HPCs in unilineage E culture. (D) Wright-Giemsa staining of vector- and siNFI-A–transduced cells. Percentage of blasts, erythroid (E), granulocytic (G), and monocytic/macrophage (Mo/Mac) cells (mean ± SEM values of 3 independent experiments). (E) Morphology of vector and siNFI-A cells at day 12 of E culture (representative field, original magnification ×400). See “Morphologic analysis” for more image information. (F) Number of BFU-E colonies generated by vector- and siNFI-A–infected HPCs (mean ± SEM values; n = 3).