Adult animals of the tom3 strain express red fluorescence in a variety of tissues. A-D: Cryosections (10 μm) were counterstained with DAPI after methanol fixation (20 min.) to visualize cell nuclei. Overlays were done with AxioVision software using false colours. Note: Due to fixation endogenous red fluorescence as well as the tissue structure suffered. Sections were made from limb muscle (A), heart (B), kidney (C) and liver (D). E-F: Macrosection of a limb bone seen in normal light (E) or with red fluorescence filter set (F). Scale bars equal 10 μm (A-D) or 1 mm (E-F).