Figure 1.

 (A) Diagram of epithelial organisation in the mouse oxyntic mucosa. Cells form a short pit opening into a gland composed of isthmus (Is), neck, and base. In the isthmus, the mutipotent stem cell gives rise to committed progenitors (pre-pit, pre-parietal, and pre-neck cells) which are responsible for the production of the four main cell types: pit, parietal, neck, and zymogenic cells. (B) Normal mouse oxyntic mucosa at postnatal day (P) 60, showing proliferating cell nuclear antigen (PCNA) labelled cells with brown nuclei which are mainly located in the isthmus (Is). (C) PCNA labelling in trefoil factor 1 knockout mouse (P60) showing a normal pattern of cell proliferation. Bar = 30 µm.