title: A protein-tagging system for signal amplification in gene expression and fluorescence imaging.
abstract: 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.
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
authors.forename: Marvin E
authors.initials: ME
authors.lastname: Tanenbaum
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biomedical Research (QB3), San Francisco, CA 94158, USA.
authors.forename: Luke A
authors.initials: LA
authors.lastname: Gilbert
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biomedical Research (QB3), San Francisco, CA 94158, USA.
authors.forename: Lei S
authors.initials: LS
authors.lastname: Qi
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biomedical Research (QB3), San Francisco, CA 94158, USA.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Weissman
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA. Electronic address: vale@ucsf.edu.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Vale
mesh_terms: D000818:Animals; D064113:CRISPR-Cas Systems; D005821:Genetic Techniques; D006801:Humans; D057054:Molecular Imaging / Q000379:methods*; D061848:Optical Imaging / Q000379:methods*; D055503:Protein Multimerization; D011506:Proteins / Q000737:chemistry*; D057127:Single-Chain Antibodies / Q000737:chemistry
chemical_list: D011506:Proteins; D057127:Single-Chain Antibodies