Changes in MS7 recognition during myeloid cell differentiation: correlation with CD11a/CD18 cell surface expression. (A) EMSA was performed on the MS7 oligonucleotide probe using nuclear extracts obtained from U937 cells (left panel) or THP-1 cells (right panel) at different time points during PMA-induced differentiation. The position of RUNX1/CBFβ- or C/EBP-containing complexes is indicated. Where indicated, unlabeled competitor oligonucleotides (MS7, MS7mutRUNX, or MS7mutCEBP) were added at 100-fold molar excess. (B) Cell surface expression of CD49d, CD11a, CD11b, CD11c, and CD18 integrin subunits on proliferating (U937) and PMA-differentiated cells (U937+PMA). Flow cytometry was performed using the indicated monoclonal antibodies.