Rosa26rtomato

Animal procedures complied with the guidelines of the European Union and protocols were approved by the local ethics committee of the Medicine Faculty, Université Libre de Bruxelles (CEBEA). Mouse strains were CD1 (Charles River), Cnx43-KI-CreER(T) (European Mouse Mutant Archive), Rosa26R-YFP and Rosa26R-Tomato (both from The Jackson Laboratory). Lgr5-DTR-EGFP knock-in mice were kindly provided by Genentech (Tian et al., 2011 (link)). The day the vaginal plug was observed was considered as E0.5.
For lineage-tracing experiments, tamoxifen (Sigma-Aldrich) was dissolved in sunflower oil (Sigma-Aldrich)/ethanol mixture (9:1) at 10 mg/ml. Pregnant females were injected intraperitoneally at 0.1 mg/g body weight. For specific cell ablation in Lgr5-DTR mice, diphtheria toxin (Sigma-Aldrich) was injected intraperitoneally (50 µg/kg) into 8-week-old mice. Control mice were injected with sterile PBS solution. Eight-week-old CD1 mice were injected subcutaneously with 300 µg/kg indomethacin (dissolved in 0.6 M NaHCO₃ buffer pH 8.5 and 5% DMSO) or with the buffer as control.

Runx3^flox (Jax 008773), p53^flox (Jax 008462), K-Ras^LSL-G12D (Jax 008179), K-Ras^LA1 (Johnson et al., 2001), Rosa26R-Tomato (Jax 007914), and Flp^ERT2 (R26^FlpoER, Jax 019016) mice were obtained from Jackson Laboratory (Bar Harbor, ME, USA). Runx3^{Frt-Stop-Frt/+} (Runx3^FSF/+) mice originated from Macrogen (Seoul, Republic of Korea). All mice analyzed had mixed genetic backgrounds and were age matched (6–8 weeks old) unless mentioned specifically. Sample size was determined based on our experience and previous experiments. No data were excluded from analysis. Animal experiments described were repeated with at least three independent replicates with significant results in the same direction as those represented in the figures. All animal studies were randomized in ‘control’ or ‘treated’ groups. However, all animals housed within the same cage were generally placed within the same treatment group. For analysis of tumor samples, identities were blinded from histopathological assessment. All animals were housed in SPF (Specific Pathogen Free) facilities. The animal studies were approved by the Institutional Animal Care Committee of Chungbuk National University.