Induction of Mcl-1 protein by PMA in U937 cells.

U937 cells were prepared for immunofluorescence confocal microscopy to show Mcl-1 expression. (A) Second-antibody only labeled PMA-treated U937 cells after 18 hours of treatment. (B) Undifferentiated U937 cells. (C) PMA-treated U937 cells after 18 hours of treatment. (D) The same as panel C, with additional PI counterstaining of nuclei. Bar = 15 μm.