Figure 3: Confocal fluorescence microscopy of cells located in the cambium layer and stained for Cbfa-1/Runx2. (a) Merged fluorescence image showing in blue the nuclear DAPI stain and in green the staining for Cbfa-1/Runx2. (b) Cbfa-1/Runx2 staining in black and white, note the nuclear expression pattern (arrow) in addition to the distinct cytoplasmic expression pattern. (c) Nuclear stain only in black and white.