Fig. 4

A high density of ac4C RNA is inside nucleoli on non-irradiated cells, and ac4C RNA colocalizes with fibrillarin. A, B Ac4C RNAs colocalize with fibrillarin-positive regions of nucleoli in non-irradiated cells. The same protein-RNA colocalization was observed in MEFs treated with actinomycin D, an inhibitor of RNA pol I. In these cells, actinomycin D treatment caused a crescent-like morphology of nucleoli, visualized by antibodies against fibrillarin. Analysis was also performed in UVA-microirradiated cells. Scale bars are 5 µm