Rosa lsl tdtomato

We obtained the heterozygous Fos-CreER^T2 mice used in this study by crossing wild-type C57BL6/J (Jackson Laboratory Stock # 000664) and Fos-CreER^T2 (+/−) mice (Jackson Laboratory Stock # 021882). We obtained heterozygous Arc-CreER^T2 mice by crossing wild-type C57BL6/J and Arc-CreER^T2 (+/−) mice (Jackson Laboratory Stock # 022357). We obtained heterozygous Fos-tTA/Fos-shGFP (+/−) mice by crossing wild-type C57BL6/J and Fos-tTA/Fos-shGFP (+/−) mice (Jackson Laboratory Stock # 018306). Fos-CreER^T2 (+/−) and Ai9 ROSA-LSL-tdTomato (+/+) mice (Jackson Laboratory Stock # 007909) were crossed to generate Fos-CreER^T2 (+/−) × ROSA-LSL-tdTomato (+/−) mice . Fos-CreER^T2 (+/−) and Fos-tTA/Fos-shGFP (+/−) mice were crossed to generate Fos-CreER^T2 (+/−) × Fos-tTA/Fos-shGFP (+/−) mice. Arc-CreER^T2 (+/−) and Fos-tTA/Fos-shGFP (+/−) mice were crossed to generate Arc-CreER^T2 (+/−) × Fos-tTA/Fos-shGFP (+/−) mice. GAD2-IRES-Cre (+/+) mice were obtained from the Jackson Laboratory (Stock # 010802). Mice were singly housed in home cages on a 12-h light/dark cycle with food and water continuously available. The light cycle was from 8 AM to 8 PM. Six- to eight-week-old mice of both sexes underwent stereotaxic brain surgery. All of the animal procedures were approved by the Institutional Animal Care and Use Committee of the University of California, Riverside.

Adult male mice (Eight to twelve weeks) were used in the experiments. The detailed information about mouse strains, including Lrp4^f/f, hGFAP::Cre and Nex::Cre has been described previously [25 (link), 51 (link)]. Rosa::LSL-tdTomato were purchased from Jackson Labs (#007909). Genotyping procedures were as follows: Lrp4^f/f, 5′-CTCTC CCAGC TAAGT CCAGG A-3′ and 5′-CCTCC ATACT GTCTG TGAAT G-3′; hGFAP::Cre, 5′-ACT CCT TCA TAA AGC CCT-3′ and 5′-GCC AGC TAC GTT GCT CAC TA-3′; Nex::Cre, 5′-GAG TCC TGG AAT CAG TCT TTT TC-3′, 5′-ATC ACT CGT TGC ATC GAC CG-3′ and 5′-CCG CAT AAC CAG TGA AAC AG-3′. In all experiments, significant efforts are made to minimize the total number of animals used while maintaining statistically valid group numbers. Mice were housed in a condition with a temperature of 22 ± 1 °C, > 30% humidity and a standard 12 h light/dark cycle. All animal experimental protocols were approved by the Animal Ethics Committee of Guangzhou Medical University.

Lgr5-EGFP-Ires-CreERT2 (Lgr5^ki, B6.129P2- Lgr5^{tm1(cre/ERT2)Cle} /J; JAX mice #008875), Rosa-lsl-tdTomato (R26R^tdTomato, B6.Cg-Gt(ROSA)26Sortm9/(CAG-tdTomato)Hze/J; JAX#007909), and Rosa-lsl-LacZ (R26R^Lacz, B6.129S4-Gt(ROSA)26Sor^tm1Sor/J; Jax #003474) mice were obtained from Jackson Laboratory. For the irradiation injury of intestinal epithelium, mice were exposed to 10 Gy TBI (Acrobio, RX-650). For lineage-tracing experiments using Lgr5^ki: R26R^tdTomato or Lgr5^ki: R26R^LacZ mice, 100 mg/kg body weight (BW) of tamoxifen (Sigma) was injected intraperitoneally 24 h before irradiation.
For lineage-tracing experiments using Atoh1^ki: Lgr5^ki: R26R^tdTomato or Atoh1^ki: R26R^LacZ mice, 2 doses of 100 mg/kg BW of RU486 (Sigma) was injected intraperitoneally at 24 h and 16 h before irradiation. In another experimental setting (Fig. S4), Atoh1^ki: R26R^LacZ mice were injected RU486 intraperitoneally for 5 consecutive days before irradiation. All experiments with mice were approved by the Institutional Animal Care Committee of Tokyo Medical and Dental University and were performed in accordance with Tokyo Medical and Dental University guidelines.