(A) One and three days following Mist1-CreERT2 induction (p.i.), typical corpus gastric units show 1–3 Rosa-mTmG reporter positive epithelial cells, which label with the chief cell marker gastric instrinsic factor (GIF). (B) One month p.i., the vast majority of Mist1 lineage traced cells (green) are basal, GSII (purple) negative chief cells. (C) Occasionally, at 1 month p.i. Mist1+ cells generate AAA positive pit cells, GSII positive mucus neck cell and VEGFB positive parietal cells. (D) At 6 months p.i., entirely marked corpus units can be detected, encompassing the GSII-marked mucous neck cells (staining of luminal cells is background), the isthmus and the pit region. Units are visualized as Z-stack reconstructions from thick tissue sections using Zeiss ApoTome (left) and multiphoton (right) technology.