Fluorescent tags

Fluorescent protein tags are fluorophores that can be transgenically expressed in living cells or organisms. This means that this technique can be used to study living cells with fluorescence microscopy, also known as live-cell imaging.

By adding a gene sequence that encodes the fluorescent tag to the gene encoding the protein through genetic engineering, a recombinant protein is created. This protein retains its original function in the cell but will fluoresce when excited at the correct wavelength. The original fluorescent protein tag is GFP: green fluorescent protein, derived from jellyfish. Newer tags such as HALO-tags or SNAP-tags tend to be smaller and brighter.