CHARACTERIZATION OF HALOTAG FLUORESCENT LIGANDS IN PLANT AND ANIMAL MODEL SYSTEMS

The isolation of green fluorescent protein (GFP) from the jellyfish revolutionized cell biology, making it possible to tag proteins for localization and dynamics by light microscopy. However, FPs still suffer from low brightness and photostability compared to fluorescent dyes. This lead to the development of genetically-encoded tags that bind to fluorescent dyes, specifically the HaloTag, a modified haloalkane dehalogenase that irreversibly binds a ligand. Like FPs, it only requires a single genetically-encoded fusion construct, but it has the superior photophysical characteristics of fluorescent dyes, yet, is still difficult to use in some organisms, such as plants, due to low cell permeability. Here we show that a newly developed HaloTag fluorescent ligand has a high permeability in plants compared to Promega TMR ligand normally used. Overall, the JF dyes extend the advantages of HaloTag to plants and provide new, fluorescent ligands for researchers using mammalian cells.