Fluorescence microscopy of cells grown in vivo (Walker carcinoma of the rat). Nuclear DNA has been stained with DAPI and counterstaining was performed with sulforhodamine 101 (SR101) for cellular protein.
DAPI forms stable complexes in the minor groove of DNA (polydA.polydT) sequences and exhibits intercalative binding to RNA (polyA.polyU) as pre- sented by Tanious et al. 1992. Picture from wikipedia.org
