Illuminating RNAs with live cell sensors

Unlike fluorescent proteins, no fluorescent RNAs have been discovered in nature. Therefore, RNAs are engineered to include fluorescent markers for tagging and tracking of RNAs in live cells. The diversity of RNA species in nature and the complex behavior in cells requires complementary approaches for a truly comprehensive toolbox that captures RNA biology in live cells. We develop and adapt tools for RNA imaging in live cells, guided by needs to visualize RNAs in our biological systems of interest.

Current work uses fluorescence lifetime imaging microscopy (FLIM) for tagging and tracking of RNAs in living systems with increasing complexity.

Two different RNA localization patterns are monitored by FLIM (panel ii, right) relative to stress granules (gold, left) and cell cytosol in live mammalian cells.
Sarfraz et al, Nat. Comm., 2023

Mammalian cells (yellow) infected with Listeria (pink)
Batan, Braselmann et al, Biophys. J., 2018

RNA dynamics at the host-pathogen interface

Infection of mammalian cells with intracellular bacterial pathogens acutely perturbs cellular processes to establish pathogen growth and dissemination within the body. Our model system is Listeria monocytogenes, the third leading cause of death from food poisoning in the United States (CDC). Listeria infection affects fundamental aspects of host RNA biology, including mRNA processing. We investigate subcellular dynamics of RNAs, proteins and bacteria in infected mammalian cells live. We are interested in both coding and non-coding RNAs, necessitating multiplexed tagging and tracking platforms to illuminate different RNA species simultaneously. Live cell fluorescence microscopy reveals insights in underlying biochemical processes while capturing heterogeneous dynamics on the single cell level.