RGS2 expression during differentiation of myeloid cell lines. (A) HL-60 cells were cultured in the presence of DMSO (▴) for granulocytic differentiation, vitamin D₃ (▦ and dotted line) for monocytic differentiation, or TPA (▪) for differentiation into macrophages. At the indicated time points, cells were removed for RNA isolation. RGS2 mRNA levels were determined by real-time RT-PCR. Monocytic differentiation was confirmed by flow cytometry for CD14, granulocytic differentiation by flow cytometry for CD11b. (B) U937 cells were treated with vitamin D₃ (⬡ and dotted line) or TPA (▴) for differentiation into monocytes or macrophages, respectively, or with ATRA (▦) for granulocytic differentiation. Samples for the analysis of RGS2 mRNA levels were taken at the indicated time points. Differentiation was confirmed by flow cytometry. (C) NB4 cells were treated with ATRA () to induce granulocytic differentiation. Samples for RGS2 mRNA determination were taken at the indicated time points. ▦ indicates ethyl alcohol. (D) NB4 cells stably transfected with Flt3-ITD were treated with ATRA. Samples for RGS2 mRNA determination were taken at the indicated time points. Symbol meaning is the same as in panel C. (E-F) Flow cytometry for CD11b after 48 hours treatment with NB4 cells (E) or NB4-Flt3-ITD cells (F). Open histograms show ethanol-treated cells and filled histograms ATRA-treated cells.