YO-TAP-3 (Oxazole Red Monomer, also known as YO-PRO®-3) is a red fluorescent carbocyanine monomeric dye. YO-TAP-3 is a cell-impermeant nucleic acid stain that is nonfluorescent in the absence of nucleic acids but exhibits significant fluorescence enhancement upon binding to DNA.
The bright fluorescence signal and low background make YO-TAP-3 ideal for staining nucleic acids on microarrays, as well as for nuclear and chromosome counterstaining in multicolor fluorescence labeling experiments.
Simultaneous labeling with cell-impermeant YO-TAP-3 and cell-permeable LUCS 13 or Annexin V-AF488 can be used to assess cell viability and apoptosis.