Figure 5.

Pulse-chase analysis of the effects of Topo II depletion on DNA replication and G₂ phase of TOP73 cells. (A) Immunoperoxidase staining of the interphase and different mitotic phases of HT1080 cells with GF-7 antibody (above); DAPI counterstaining of DNA (below). (B) Flow cytometric analysis of changes in DNA content of TOP73 cells that were pulse-labeled with EdU 40 h after culture in the absence (above) or in the presence of doxycycline (below) at the indicated time points after the removal of EdU. Only EdU-positive cells are shown. (C) Flow cytometric analysis of EdU and GF-7 labeling of TOP73 cells that were pulse-labeled with EdU 40 h after culture in the absence (above) or in the presence of doxycycline (below), at the indicated time points after the removal of EdU. Percentages of EdU⁺ GF-7⁻ and EdU⁺ GF-7⁺ cells are shown. (D) Time course of mitotic entry in TOP73 cells, untreated or treated with doxycycline. Percentages of EdU⁺ GF-7⁺ cells from (C) are plotted.