A Far-Red Emitting Fluorescent Chemogenetic Reporter for In Vivo Molecular Imaging

Angew Chem Int Ed Engl. 2020 Oct 5;59(41):17917-17923. doi: 10.1002/anie.202006576. Epub 2020 Aug 18.


Far-red emitting fluorescent labels are highly desirable for spectral multiplexing and deep tissue imaging. Here, we describe the generation of frFAST (far-red Fluorescence Activating and absorption Shifting Tag), a 14-kDa monomeric protein that forms a bright far-red fluorescent assembly with (4-hydroxy-3-methoxy-phenyl)allylidene rhodanine (HPAR-3OM). As HPAR-3OM is essentially non-fluorescent in solution and in cells, frFAST can be imaged with high contrast in presence of free HPAR-3OM, which allowed the rapid and efficient imaging of frFAST fusions in live cells, zebrafish embryo/larvae, and chicken embryos. Beyond enabling the genetic encoding of far-red fluorescence, frFAST allowed the design of a far-red chemogenetic reporter of protein-protein interactions, demonstrating its great potential for the design of innovative far-red emitting biosensors.

Keywords: biosensors; chemogenetic reporters; chromophores; far-red fluorescence; in vivo imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chick Embryo
  • Fluorescent Dyes / chemistry*
  • HeLa Cells
  • Humans
  • Molecular Imaging / methods*
  • Protein Binding
  • Zebrafish / embryology


  • Fluorescent Dyes