Visualising G-quadruplex DNA dynamics in live cells by fluorescence lifetime imaging microscopy

Peter Andrew Summers, Ben Lewis, Jorge Gonzalez-Garcia, Aaron H M Lim, Paolo Cadinu, Rosa Maria Porreca, Nerea Martin-Pintado, David Mann, Joshua B Edel, Jean-Baptiste Vannier, Marina Kuimova, Ramon Vilar

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Received Date: 26th March 20

Guanine rich regions of oligonucleotides fold into quadruple-stranded structures called G-quadruplexes (G4). Increasing evidence suggests that these G4 structures form in vivo with a crucial role in cellular processes, however, their direct observation in live cells remains a challenge. Here we unequivocally demonstrate that a fluorescent probe (DAOTA‑M2) in conjunction with Fluorescence Lifetime Imaging Microscopy (FLIM) can identify G4 within nuclei of live and fixed cells. We have developed a new FLIM-based cellular assay to study the interaction of non-fluorescent small molecules with G4, which can be applied to a wide range of drug candidates. We demonstrate that DAOTA‑M2 can be used to study G4 stability in live cells. Disruption of FancJ DNA helicase activity increases G4 lifetime, directly establishing for the first time its biological activity in mammalian cells.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

Nature Communications

Nature Research, Springer Nature