Cell Cycle and Cell Proliferation Markers

Current concepts in cell biology suggest that there are checkpoints in the various phases of the cell cycle at which cells are monitored for damage to their DNA. Studies in our laboratory on the effect of radiation on cells in culture have shown delay of progression in both the G1 and G2 phases of the cell cycle of normal, non-transformed cells. It has been proposed that the delay period in these phases allows time for cells to repair DNA damage before proceeding to the next phase of the cell cycle. Thus cells in G1 would be required to repair potential DNA damage prior to entering S phase in order to alleviate the possibility of replicating an abnormal and potentially malignant genome. Studies on the regulations at the proposed checkpoints are important for elucidating cell cycle control mechanisms. Such investigations require techniques that can continuously monitor the distribution of cell throughout the cell cycle and access the proliferation potential of cells in different phases of the cell cycle.