Figure 6.
Distribution of OTC transgene expression across the hepatic lobule. OTC enzyme activity was examined in liver sections (5 µm) from wild-type, untreated, and vector-treated Spfash mice using an in situ histochemical staining method. Cells expressing OTC stain brown with an intensity that correlates with the level of enzymatic activity. Sections from (a) wild-type and (b) untreated adult Spfash mice. (c) Liver section from an adult mouse injected (i.p.) with 1.5 × 1011 vg and harvested 1 month later. Note higher intensity OTC staining around the central vein. (d) Counterstaining with an antibody to glutamine synthetase antibody to unequivocally identify the central veins. Liver sections from Spfash mice injected (i.p.) at 1.5 days and harvested (e) 2 and (f) 8 weeks postinjection. Note appearance of clusters of OTC-expressing cells. Bar = 100 µm. i.p., intraperitoneally; OTC, ornithine transcarbamylase; Spfash, OTC-deficient; vg, vector genome; wt, wild-type.