Fig. 5

UVC light caused an accumulation of ac4C RNA into well-visible foci in a later stage of DDR. A In non-irradiated control cells, relatively high ac4C RNA positivity was observed in nucleoli (detected using immunostaining by the use of an antibody against fibrillarin). UVC irradiation increased the level of ac4C RNA in the whole nucleoplasm (the most marked changes were 5–20 min post-irradiation). MEFs analyzed 20–120 min after UVC irradiation were characterized by ac4C RNA reorganization into well-visible and ac4C RNA-dense tiny foci. Scale bars showed 5 µm. B Quantification shows the fluorescent intensity (FI) of ac4C RNA in the nucleoplasm (green) compared with fibrillarin-positive regions of nucleoli (red) and DAPI-stained DNA (blue). Quantification by LAS X software was performed across the green lines, shown in panel A. C Box plot graphs display the absolute intensity of ac4C RNA in the nucleoplasm (nucleus), ****p ≤ 0.0001 (ANOVA One-Way test). D Box plot graphs show the total intensity of fluorescently-stained ac4C RNA in nucleoli, ****p ≤ 0.0001, **p ≤ 0.01. E Box plot graphs depict the ratio of the fluorescent intensity of ac4C RNA occupying nucleoli and the nucleoplasm (whole nucleus), ****p < 0.0001