Extended Data Fig. 1: Validation of a Cldn18–IRES–CreERT2 stomach–specific line.

(a) IF images of Cldn18 (red) and E–cadherin (green) co–staining in small intestine, colon, esophagus, liver and pancreas (n = 5 biological replicates). (b) IF images of tdTomato tracing at 24 hrs, 1 week and 6 months post–tamoxifen induction in the small intestine, colon, esophagus, liver and pancreas from Cldn18–dTom mice (n = 5 biological replicates). (c) IF images of Cldn18 (red) and E–cadherin (green) co–staining in pylorus regions from Cldn18–CreERT2 wild–type (top, n = 3 biological replicates), heterozygous (middle, n = 3 biological replicates) and homozygous (bottom, n = 3 biological replicates) mice. (d) IF images of Cldn18 (red) and E–cadherin (green) co–staining in corpus regions from Cldn18–CreERT2 wild–type (top, n = 3 biological replicates), heterozygous (middle, n = 3 biological replicates) and homozygous (bottom, n = 3 biological replicates) mice. (e) IF images of β–catenin (blue) and ZO–1 (magenta) co–staining in pylorus regions from Cldn18–CreERT2 wild–type (top, n = 3 biological replicates), heterozygous (middle, n = 3 biological replicates) and homozygous (bottom, n = 3 biological replicates) mice. (f) IF images of β–catenin (blue) and ZO–1 (magenta) co–staining in corpus regions from Cldn18–CreERT2 wild–type (top, n = 3 biological replicates), heterozygous (middle, n = 3 biological replicates) and homozygous (bottom, n = 3 biological replicates) mice. (g) IF images of pyloric lineage markers from uninduced Cldn18–dTom mice (top, n = 3 biological replicates) and induced mice (bottom, n = 3 biological replicates) 1 month post induction for Gastrin, Muc5 and Ki67 (yellow) and tdTomato (red). (h) IF images of corpus lineage markers from uninduced Cldn18–dTom mice (top, n = 3 biological replicates) and induced mice (bottom, n = 3 biological replicates) 1 month post induction for GIF, H⁺ pump, Muc5 and Ki67 (yellow) and tdTomato (red). Scale bars 100 μm.