A protein-tagging system for signal amplification in gene expression and fluorescence imaging.
- Author(s): Tanenbaum, Marvin E;
- Gilbert, Luke A;
- Qi, Lei S;
- Weissman, Jonathan S;
- Vale, Ronald D
- et al.
Published Web Locationhttps://doi.org/10.1016/j.cell.2014.09.039
Signals in many biological processes can be amplified by recruiting multiple copies of regulatory proteins to a site of action. Harnessing this principle, we have developed a protein scaffold, a repeating peptide array termed SunTag, which can recruit multiple copies of an antibody-fusion protein. We show that the SunTag can recruit up to 24 copies of GFP, thereby enabling long-term imaging of single protein molecules in living cells. We also use the SunTag to create a potent synthetic transcription factor by recruiting multiple copies of a transcriptional activation domain to a nuclease-deficient CRISPR/Cas9 protein and demonstrate strong activation of endogenous gene expression and re-engineered cell behavior with this system. Thus, the SunTag provides a versatile platform for multimerizing proteins on a target protein scaffold and is likely to have many applications in imaging and controlling biological outputs.