OTC labeling in infected and uninfected hepatocytes. The ultrathin frozen liver section from a spfash mouse infected with Ad.mOTC was labeled by the rabbit anti-OTC antibody followed with gold-conjugated goat anti-rabbit antisera. The hepatocyte infected with the OTC virus is characterized by enlarged mitochondria and a much higher mitochondrial OTC labeling density (upper right corner) than in the uninfected hepatocyte (lower left corner). TJ, tight junction complex; BC, bile canaliculus; ER, endoplasmic reticulum. Arrows indicate the lateral membrane of the hepatocytes. Bar, 0.1 µm.