Figure 4

The dynamics of α-satellite DNA during cellular senescence. (a) Live imaging procedure of α-satellite DNA during cellular senescence. (b) Coefficient of variation of the GFP domain size in nontreated and 5-Aza-dC-treated cells. Over 75 GFP domains were analysed. The error bars show the SEM. The p-value was calculated using Student’s t-test; ***p < 0.05. (c) Comparison of GFP domain fluctuation. The frequency of the GFP domain area showing > 30% variation from the area at time 0 within 30 min during observation was calculated in nontreated and 5-Aza-dC-treated cells. The error bars show the SEM. The p-value was calculated using the Student’s t-test; ***p < 0.05. (d) Live observation of α-satellite DNA in nontreated and 5-Aza-dC-treated hTERT-RPE1 cells using CRISPR imaging. The GFP domain areas, indicated by arrowheads with numbers, were monitored during observation. The GFP domains enclosed by white boxes are enlarged. Scale bar: 10 μm. (e) The relative area to the size at 0 min for each GFP domain was monitored during live imaging. The numbers (1–4 for nontreated and 1–4 for 5-Aza-dC-treated cells) correspond to the numbers of GFP domains shown in (d).