3,5-difluoro-4-hydroxybenzylidene imidazolinone-2-oxime ( DFHO )

- Overview
  - DFHO is a non-fluorescent dye that is structurally similar to the chromophore found in red fluorescent protein (RFP). Upon binding to the Corn™ aptamer, DFHO is converted to a highly fluorescent state that can be detected at the emission wavelength of 545 nm. DFHO can also bind Broccoli™ derivative aptamers and turn on their fluorescence. DFHO is cell-permeable with negligible toxicity in living cells and can be used to label any genetically encoded Corn™ RNA tag. When bound to Corn™, DFHO has been found to be highly photostable compared to DFHBI, DFHBI-1T, and mVenus. The photostability of DFHO was demonstrated in the imaging and quantitative measurement of cellular Pol III promoter activity in living cells.
    
    A. Live-cell imaging of HEK293T cells expressing U6 promoter driven Corn™ in the presence of 10 µM DFHO. Images are Hoechst-stained nuclei (blue) and Corn™ fluorescence (yellow), individually or overlayed. Images were acquired using YFP and DAPI filter sets.
    B. Live-cell imaging of E. coli cells expressing tRNA promoter driven Corn™ in the presence of 10 µM DFHO.
    
    Please contact us at for specific academic pricing.
    
    More Details
    
    Fluorophores for Imaging RNA in Living Cells
- Properties
  - Categories
    
    Fluorophores
    
    Storage
    
    Stable in the dark for 2 year at -20 °C.
    
    Alternative Name
    
    DFHO
    
    CAS Number
    
    1420815-34-4
    
    Molecular Formula
    
    C12H9F2N3O3
    
    Molecular Weight
    
    281.2
    
    Appearance
    
    Lyophilized dye
    
    Other Properties
    
    Products are analyzed by 1H NMR and LC-MS and provided at purity of >95% by HPLC.
    
    * This product is intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.
- Applications
  - Application Description
    
    DFHO binds to the Corn aptamer or Broccoli derivative aptamers for imaging RNA in living cells.
- Reference
  - Imaging RNA polymerase III transcription using a photostable RNA-fluorophore complex. Song W, Filonov GS, Kim H, Hirsch M, Li X, Moon JD, Jaffrey SR. Nat Chem Biol. 2017 Nov;13(11):1187-1194.
    A homodimer interface without base pairs in an RNA mimic of red fluorescent protein. Warner KD, Sjekloca L, Song W, Filonov GS, Jaffrey SR, Ferre-D’Amare AR. Nat Chem Biol. 2017 Nov;13(11):1195-1201.
    Spectral tuning by a single nucleotide controls the fluorescence properties of a fluorogenic aptamer. Filonov GS, Song W, Jaffrey SR. Biochemistry. 2019 Mar 26;58(12):1560-1564.