Effect of ERK-dependent hnRNP-E2 down-regulation on C/EBPα expression and neutrophilic differentiation of 32D-BCR/ABL^high cells.(A) Protein levels of C/EBPα and hnRNP-E2 in newly established 32Dcl3 cell clones expressing different levels of p210-BCR/ABL (top panel). Levels of C/EBPα, hnRNP-E2, phospho-ERK1/2, total ERK1/2, and BCR/ABL in 32Dcl3 cells and untreated, imatinib-treated, and U0126-treated 32D-BCR/ABL cells expressing high levels of the p210-BCR/ABL oncoprotein (32D-BCR/ABL^high) (bottom panel). Cells were cultured in the presence of IL-3 or G-CSF. (B) REMSA with ³²P-labeled WT-uORF/spacer CEBPA oligoribonucleotide probe and cytosolic lysates from 32Dcl3 cells and untreated, imatinib-treated, and U0126-treated 32D-BCR/ABL^high cells (left panel). Expression of Gr-1 on 32Dcl3 and untreated, U0126-treated, and CI-1040–treated 32D-BCR/ABL^high cells upon G-CSF stimulation for 4 days (right panel). (C) May-Grunwald/Giemsa staining of 32Dcl3 and 32D-BCR/ABL^high cells cultured with IL-3 or G-CSF for 7 days in the presence or absence of imatinib, U0126, or CI-1040.