Long-term expression after AAV1/2 transduction. Wild-type mice obtained a single intrahepatic AAV-EGFP injection containing 4.5 × 109 tu on day 6. After 10.5 months the mice were perfused with 4% paraformaldehyde. Tissue for expression analysis was cryoprotected in sucrose and stored frozen at -80° until analysis. Cryostat sections of 3 μm thickness were prepared for EGFP expression analysis. Pictures were recorded by Fluorescent microscope BX60 from Olympus. Fluorescence is shown as an overlay of EGFP (green) and nuclear DAPI (blue) fluorescence. The images were recorded with an exposure time of 50 ms for DAPI and 500 ms for EGFP (1 s for negative expression).