Stealth Fluorescence Labeling for Live Microscopy Imaging of mRNA Delivery
Artikel i vetenskaplig tidskrift, 2021

Methods for tracking RNA inside living cells without perturbing their natural interactions and functions are critical within biology and, in particular, to facilitate studies of therapeutic RNA delivery. We present a stealth labeling approach that can efficiently, and with high fidelity, generate RNA transcripts, through enzymatic incorporation of the triphosphate of tCO, a fluorescent tricyclic cytosine analogue. We demonstrate this by incorporation of tCO in up to 100% of the natural cytosine positions of a 1.2 kb mRNA encoding for the histone H2B fused to GFP (H2B:GFP). Spectroscopic characterization of this mRNA shows that the incorporation rate of tCO is similar to cytosine, which allows for efficient labeling and controlled tuning of labeling ratios for different applications. Using live cell confocal microscopy and flow cytometry, we show that the tCO-labeled mRNA is efficiently translated into H2B:GFP inside human cells. Hence, we not only develop the use of fluorescent base analogue labeling of nucleic acids in live-cell microscopy but also, importantly, show that the resulting transcript is translated into the correct protein. Moreover, the spectral properties of our transcripts and their translation product allow for their straightforward, simultaneous visualization in live cells. Finally, we find that chemically transfected tCO-labeled RNA, unlike a state-of-the-art fluorescently labeled RNA, gives rise to expression of a similar amount of protein as its natural counterpart, hence representing a methodology for studying natural, unperturbed processing of mRNA used in RNA therapeutics and in vaccines, like the ones developed against SARS-CoV-2.


Tom Baladi

Chalmers, Kemi och kemiteknik, Kemi och biokemi

AstraZeneca AB

Jesper Nilsson

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Audrey Gallud

Chalmers, Biologi och bioteknik, Kemisk biologi

Emanuele Celauro

Chalmers, Biologi och bioteknik, Kemisk biologi

Cécile Gasse

Université d'Évry Val-d'Essonne

Fabienne Levi-Acobas

Institut Pasteur, Paris

Ivo Sarac

Institut Pasteur, Paris

Marcel R. Hollenstein

Institut Pasteur, Paris

Anders Dahlén

AstraZeneca AB

Elin Esbjörner Winters

Chalmers, Biologi och bioteknik, Kemisk biologi

Marcus Wilhelmsson

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 143 14 5413-5424


Nanovetenskap och nanoteknik

Hälsa och teknik


Fysikalisk kemi


Biokemi och molekylärbiologi

Medicinsk bioteknologi (med inriktning mot cellbiologi (inklusive stamcellsbiologi), molekylärbiologi, mikrobiologi, biokemi eller biofarmaci)

Organisk kemi





Mer information

Senast uppdaterat