Figure 4. proTAME blocks HT induced mitotic exit. (A) Microscopy analysis based on DNA morphology of mitotic index (MI) and mitotic catastrophe (MN). HEp2 cells were treated with 12 µM proTAME for 5 and 6 h or 10 nM PTX for a total time of 18 h. After 12 or 13 h of PTX exposure proTAME was added and cells were heat shocked for 1 or 2 h at 42 °C and then returned to 37 °C for additional 4 h. A minimum of 1000 cells were counted for each sample. (B) Western blot analysis of cyclin B stability in cells treated as in (A). Addition of proTAME inhibits HT induced mitotic exit by micronucleation.