Cell Cycle Assay Kit

Measurement the amount of DNA is usually used to monitoring cell cycle progression. The cell cycle consists of G1, S, G2, and M phases. In the G1 phase, the DNA content of the cells is the lowest (2N), and in the S phase, the DNA begins to replicate, the DNA content gradually increases, and by the G2 and M phases, the DNA content doubles (4N).

Cell Cycle Assay Kit is a kit for cell cycle detection by propidium iodide PI. PI is a nuclear dye that is able to cross the cell membrane to stain dead or fixed cells, but not the membrane of living cells. When stained with propidium iodide, cells at different cell cycle stages exhibit different fluorescence intensities. Cells in the G0/G1 phase have a fluorescence intensity of 1 because they contain a copy of genomic DNA. Cells in the G2/M phase, on the other hand, have a fluorescence intensity of 2 because they contain double genomic DNA. The fluorescence intensity of cells in the S phase is between 1 and 2. Apoptotic cells, exhibit weaker fluorescence intensities during staining, typically less than 1. This is because the concentration of the nucleus during apoptosis is accompanied by DNA fragmentation, resulting in the loss of some genomic DNA fragments. On the fluorescence detection map of the flow cytometer, this phenomenon appears as the so-called sub-G1 peak, which marks the presence of apoptotic cells.