HeLa cell response to mitomycin C. I. cell division.

The effect of mitomycin C (10 μg/mL) on HeLa-M cells was studied using light microscopy, time-lapse imaging, and digital image analysis. It was shown that after 2 h of being in contact with mitomycin, the cells could be divided into two groups: M-I, functional cells surviving after division but not entering mitosis, and M-II, cells entering mitosis but incapable to complete it, which results in their death. It is known that mitomycin C, being located in the DNA minor groove, specifically blocks DNA replication. According to the standard hypothesis of transcription bubble formation, it should inhibit RNA synthesis. However, the increase in the cell and nucleolus area during the M-I cell growth suggests that RNA and protein synthesis are not blocked. I conclude that these findings confirm my hypothesis of RNA synthesis in the main DNA groove without its local melting (Petrov, 2006). [ABSTRACT FROM AUTHOR]