Acta2 creert2

The knock-in Prrx1^CreERT2 mouse line was generated by Shanghai Biomodel Organism Science & Technology Development Co., Ltd. In this study, heterozygous Prrx1^CreERT2 mice were used for lineage tracing or gene ablation. Rosa26^LSL-tdTomato, Acta2-CreERT², and Col1a2-CreERT² mice were purchased from the Jackson Laboratory (https://www.jax.org/cn/). Bmpr1a^f/f mice were generated in Yuji Mishina’s laboratory. Animal experiments were carried out in accordance with recommendations in the National Research Council Guide for Care and Use of Laboratory Animals and in comply with relevant ethical regulations for animal testing and research, with the protocols approved by the Institutional Animal Care and Use Committee of Shanghai, China (SYXK(SH)2011–0112). This study follows the project that ‘Studies on the mechanism of MSC self-renewal differentiation and regulation of related tissue stem cells,’ which was approved by Shanghai Jiao Tong University in 2015 and 2024, the approval number is A2015027 and A2024014. Male mice were used in this study. Mice were anesthetized using 40 mg kg^–1 sodium pentobarbital by intraperitoneal injection or euthanized by carbon dioxide inhalation.

Mice were maintained in the Animal Research Center and experiments were performed under a protocol approved by the Institutional Animal Care and Use Committee of Yale University. For inducible Cre-mediated recombination, Nck1−/−;Nck2flox/flox mice^{29 (link)} (129/SVJ), Pdgf-bflox/flox mice^{32 (link)} (C57BL/6J) and mTmG reporter mice (The Jackson Laboratory, 129/SVJ) were bred with Cdh5-CreERT2 mice^{59 (link)} (C57BL/6J), Pdgfrβ-CreERT2 mice^{60 (link),61 (link)} (129/SV;C57BL/6J mixed background), SMACreERT2 mice^{62 (link)} (or ACTA2-CreERT2, FVB/NJ), and Myh11CreERT2 mice (The Jackson Laboratory, FVB/NJ). Gene deletion was induced by intraperitoneal injections with 50 μg tamoxifen (Sigma, T5648; 1 mg/ml) to pups at P0, P1, and P2, and mice were sacrificed at P5. The Cre-negative, tamoxifen-treated littermates are used as control mice. For genetic cell fate tracking, CRE activity was induced by two consecutive intraperitoneal injections of pups at P6 and P7 with 50 μg tamoxifen solution.