Differentiation status, cell cycle distribution, and PML-staining patterns of NB₄ cells at distinct time-points of an ATRA treatment.

Differentiation of the cells was evaluated by (A) morphological changes (Wright's staining) and (B) CD11b expression. (C) The percentages of G₁/G₂- and S-phase cells at the same time-points were measured by PI staining and FACS analysis. (D) PML/RAR, PML localization in corresponding time-points was studied using immunofluorescence methods with antihuman PML antibodies.