A Carbonized Fluorescent Nucleolus Probe Discloses RNA Reduction in the Process of Mitophagy

Abstract

Mitophagy is a complicated process of cell metabolism that exhibits dynamic spatiotemporal coordination between multiple organelles. Despite its relevance to nucleoli, visualizing the distribution of nucleolar RNA in the process of mitophagy remains a great challenge because of the difficulty in specifically labeling RNA. Herein, we demonstrate a robust carbonized fluorescent probe with folic acid (FA) and m-phenylenediamine (m-PD) as the precursors, which displays superior RNA-anchoring ability and fast cellular permeability to tag nucleolar RNA in living cells. More importantly, this probe possesses spontaneous blinking behavior in physiological conditions, which is suitable for nanoscopic imaging of subtle changes in the distribution of nucleolar RNA. Overall, this work presents a new way for in situ observation of nanoscopic behavior of nucleolar RNA in living cells, providing a powerful approach for further exploration of cellular metabolism in mitophagy.