NET23/STING chromatin effects may set the stage for a transitional state between chromatin condensation and apoptosis.

<p>(<b>A</b>) Cells were taken at 23 h post-transfection and stained for DNA and the characteristic early apoptosis marker annexin V. GFP-transfected cells exhibit a normal distribution pattern with a large annexin V-negative G1 population (close to 100K) and smaller annexin V-negative G2/M population (close to 200K) and a small (∼10%) sub-G1 population that is mostly annexin V-positive. In contrast, at this early time post-transfection the NET23/STING-transfected population yields an aberrant distribution pattern with the main cell populations slightly lower than the normal G1 population, yet still slightly larger than the apoptosing sub-G1 population. This may reflect the process of chromatin condensation. (<b>B</b>) To investigate this population further, NET23/STING-transfected cells were analyzed over a timecourse from 17 to 66 h post-transfection. Over time the higher sub-G1 population can be observed to initially increase and then diminish as the smaller sub-G1 population increases. The density plots shown on the left plot DNA content against forward scatter to measure overall cell size/shape and thus likely give information about the shift in chromatin compaction, but these plots can be misleading about total numbers because of spots representing individual cells being printed on top of one another. In contrast, the cell cycle population plots on the right clearly show the total percentage of cells for the initial appearance of a higher sub-G1 population followed by its chasing into an apoptotic smaller/fragmented sub-G1 population.