Imaging of RNA in live cells

Fluorescence microscopy and molecular tagging technologies have ushered in a new era in our understanding of protein localization and function in cells. This review summarizes recent efforts to extend some of these methods (and to create new ones) to imaging of RNA in live cells. Both fluorescent proteins and hybridization probes allow noncovalent labeling of specific RNA molecules with fluorescent dyes that allow detection and tracking in real time.

► RNA is inherently nonfluorescent, so fluorophores must be delivered to the RNA.
► Live-cell RNA imaging has advanced due to the availability of new molecular-labeling technologies.
► Fluorescent protein–RNA binding protein fusion constructs now permit multicolor labeling for imaging of multiple RNAs simultaneously.
► New hybridization probe designs offer improved brightness, higher affinity, better delivery into cells, and avoidance of nuclease enzymes and nuclear sequestration.