Fig. 4. DN-PLK1 induces abnormal mitoses in SAOS-2 and U-20S but not in HMECs. Cells were infected at 200 MOI of dnPLK1 and processed for immunohistochemistry at different time points. SAOS-2 cells immunostained 24 h postinfection for {alpha}-tubulin (A), {alpha}-tubulin and DAPI (B), or gamma-tubulin (C). Arrows, abnormal prophase mitoses with disrupted mitotic spindles and poor centrosomal {gamma}-tubulin staining. U-2OS cells immunostained 48 h postinfection for {alpha}-tubulin (D). Arrows, abnormal prophase and metaphase cells. HMECs were immunostained 48 h postinfection with {alpha}-tubulin and DAPI (E) or {gamma}-tubulin (F). Arrow, prophase cell with normal monoastral spindle. Metaphase cell is just below.