Fig. 7.

CEP-11004 delays nuclear histone H3 phosphorylation in early prophase. HeLa cells grown on coverslips were synchronized at G1/S with excess thymidine and released back into the cell cycle. At 5 h after release, cells were incubated in the absence or presence of CEP-11004 (500 nM). After an additional 4 h incubation (9 h after G1/S release), cells were fixed and co-immunostained for cyclin B1 or phosphorylated histone H3 (pH3) in the top and middle panels, respectively, of (A). MLK3 and cyclin B1 expression are shown in the top and middle panels, respectively, of (B). Mitotic cells (indicated by arrows) were determined by the presence of nuclear cyclin B1 and/or pH3 staining. Cells in (A) and (B) were counterstained with DAPI (lower panels).