Expression of ASS in the small intestine, kidney and liver of ND14 mice.

ASS protein in the duodenum (panels A, B, E, F) and ileum (panels C, D, G, H) of Ass-Con or Ass-KO/I animals is visualized by semiquantitative immunohistochemistry. The second row of panels shows magnifications of the top row. Note that expression of ASS in Ass-Con mice is limited to the top portion of the villus. Further note that the elimination of Ass expression is complete in the enterocytes of Ass-KO/I mice, but unaffected in their enteric ganglia (arrows). The bottom panels show unperturbed ASS protein in the S3 segment of the proximal tubule of the kidney (J, K) and in the periportal region of the liver (L, M) of Ass-KO/I mice. Gray bars identify Ass-Con and black bars Ass-KO/I mice. Bars: 8 µm (overviews) and 1 µm (magnifications).