Figure 8.

 Schematic representation of the effects of trefoil factor 1 (TFF1) knockout (KO) on the commitment programme leading to the three main cell lineages of the oxyntic mucosa. The stem cell normally gives rise to pre-pit, pre-parietal, and pre-neck cells which differentiate into pit, parietal, and neck cells, respectively. The latter changes its phenotype and becomes a zymogenic cell through a pre-zymogenic stage. Note that both pre-pit and pre-neck cells also give rise to a small proportion of pre-parietal cells. Normal expression of TFF1, TFF2, and TFF3 is indicated. In TFF1 KO animals, the pit cell compartment is increased at the expense of the parietal cell compartment, suggesting that TFF1 is required for pre-pit to pre-parietal commitment.