Cells in sub-G1 phase of cell cycle are described as cumulative apoptosis. Could anyone illustrare more details about this type of apoptosis?
Thanks!
I think this paper gives a decent explanation and diagram.
“2.6. Flow cytometry-based assays for cellular morphology and DNA fragmentation
Irinciple that after DNA endonucleolytic cleavage, the fragmented low-molecular-weight DNA is released from cells during prolonged fixation. That will yield a population of cells that binds a quantitative DNA stain, PI, to a lesser extent than what is characteristic for G1 cells; G1 represents the longest phase of the cell cycle and, therefore, the largest fraction of cells are typically in G1. As a result, there will be a population of cells that appears to the left of the G1 peak (see NOTE 3).”. dna loss due to fragmentation caused accumulation in the sub-G1 flw cytometry peak.Article Chapter 6 DNA Damage Response and Apoptosis
Rather than a single time snapshot, progressive time points follow cumulative shift to sub-G1 peak. Article Phototoxicity of Hoechst 33342 in time-lapse fluorescence microscopy
Apoptosis causes DNA fragmentation, therefore you will see a lower content of DNA when stayining with intercalading dies (eg. Propodium Iodide) and quantifying with FACS. The sub-G1 phase appears on the left, preceeding the G1 phase and includes all those cells with reduced DNA content for one reason or another. However, the sub-G1 phase not only includes apoptotic cells, but also other types of cell deaths which might be indistinguishable when analyzing via FACS. One has to be careful when interpreting the sub-G1 phase as apoptosis, since it could also include cells that have been damaged by mechanical stress (necrosis). Moreover, early apoptosis (eg. prior to DNA fragmentation) is not detectable in the sub-G1 phase. Sub-G1 analysis should always be accompanied by other assays to confirm presence of apoptosis, such as Annexin V/PI staining, PARP1 cleavage, Caspase-3 activation etc....
For further info about molecular mechanisms of cell death: https://www.nature.com/articles/s41418-017-0012-4
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Cell Biology
- Culture Cells
- Cell Line