Fig. 5. Visualisation of transcription sites in interphase nuclei by BrUTP incorporation into unfixed wheat root seedling sections. Stereo pairs of 3D confocal stacks are shown. (A) Control seedling germinated in water. (B) Seedling germinated in 5-AC. (C) Seedlings germinated in TSA. The BrUTP labelling comprises many small punctate foci dispersed throughout the nucleus (Abranches et al., 1998), and there is no obvious difference in the overall organisation of the nuclear transcription sites after either treatment. The labelling of transcription is particularly strong in the nucleolus and comprises intranucleolar foci that are closely associated, much like closely packed beads on a string, and organised in a network of strands throughout the nucleolus. Bar, 10 µm.