Hoechst S769121 (Nuclear Yellow) is a cell-permeant yellow-emitting fluorescent dye that binds strongly to adenine-thymine-rich regions in the minor groove of double-stranded DNA. Although Nuclear Yellow can bind to all nucleic acids, AT-rich dsDNA strands enhance its fluorescence considerably.
Nuclear Yellow is used in fluorescence microscopy, fluorometry, and flow cytometry to stain and measure DNA content in live and fixed cells. It is commonly used in combination with retrograde tracers such as True Blue for two-color neuronal imaging. Nuclear Yellow can also be used to photoconvert diaminobenzidine (DAB) into an electron-dense reaction product for light and electron microscopy applications.
The commonly used dye concentration to stain bacteria or eukaryote cells is 0.1–10 μg/mL.
