DBC1 localization and expression during cell cycle progression.A, immunofluorescence microscopic analysis of DBC1 in different stages of cell cycle in U2OS cells, as indicated. DAPI staining (blue) was used to stain the DNA and ascertain the cell cycle stage. Green staining shows DBC1 and red staining indicates β-Tubulin. The images are representative of three independent experiments (63× magnification; the scale bar represents 10 μm). The data are representative of at least three independent experiments. B, localization of DBC1 (green) and tubulin (red) at the mid-body during cytokinesis. A magnified size of the merged image of the same experiment is also shown. C, Western blot showing increased DBC1 protein amounts in U2OS cells, after release from thymidine block. Mitotic stage was apparent at about 9 to 11 h after thymidine release, as was confirmed by enhanced cyclin B1 signals. The asterisks (∗) at 4 h and 9 h indicate that the DBC1 levels clearly increase during the S and G2/M phases, respectively. DBC1, deleted in breast cancer 1.