Prrx1 cre

C57Bl/6J (RRID: IMSR_JAX:000664), Rosa26^Cas9 (RRID: IMSR_JAX:024858), Rosa26^FLP (RRID: IMSR_JAX:003946) and Prrx1Cre (RRID: IMSR_JAX:005584) mouse strains were obtained from the Jackson Laboratory. Slc38a2^LacZ (C57BL/6N-ASlc38a2/Wtsi Ph) was purchased from the European Mouse Mutant Archive. To generate Slc38a2^flox, Slc38a2^LacZ mice were crossed to Rosa26^FLP to remove FRT-flanking LacZ cassette followed by a backcrossing with C57Bl/6J to remove Rosa26^FLP allele. Mice were housed at 23°C on a 12-h light/dark cycle with free access to water and PicoLab Rodent Diet 20 (LabDiet #5053, St. Louis, MO). All mouse procedures were approved by the Animal Studies Committees at Duke University first and then the University of Texas Southwestern Medical Center.

Mice were maintained on a C57BL/6J background and bred in an environmentally controlled specific pathogen free room at 23 ± 2°C with 50–60% relative humidity under a 12-hour light/dark cycle. Noon of the day on which a vaginal plug was seen was considered as E0.5.
We obtained Msx2-Cre mice [23 (link)] from the Mutant Mouse Resource Research Center (Davis, CA, USA), Prrx1-Cre [24 (link)] and Rosa-CAG-LSL-tdTomato (Ai14) mice [25 (link)] from the Jackson Laboratory (Bar Harbor, ME, USA), and CAG-Cre mice [26 (link)] from RIKEN BRC (Ibaraki, Japan). The mice with p63 floxed allele were generated as described previously [27 (link)]. To generate CAG-EGFP-TAp63γ mice, a transgene was constructed as described previously [28 (link)]. DNA purification and microinjection were performed according to standard protocols. Genotyping was performed by PCR using genomic DNA from mouse tails, KOD FX DNA polymerase (Toyobo, Osaka, Japan), and specific primers (S1 Table).

Floxed Osterix (Osx^fl/fl) mice^{28 (link)} were a gift from B. de Crombrugghe (University of Texas MD Anderson Cancer Center). PthrP-mCherry mice^{2 (link)} were a gift from Noriaki Ono (UT Health School of Dentistry). Rosa26-tTA mice²⁹ were a gift from Luigi Puglielli (University of Wisconsin-Madison). Rosa26^confetti (Stock 017492), NOD scid gamma (NSG, Stock 005557), NSG-EGFP (Stock 021937), Rosa26^mT/mG (Stock 007676), R26-M2rtTA (Stock 006965), pTRE-H2BGFP (Stock 005104), Prrx1-cre (Stock 005584), Ocn-cre (Stock 019509), Pax7-cre (Stock 010530), Shh-cre (Stock 005622), Mpz-cre (Stock 017927), MIP-GFP (Ins1-EGFP, Stock #: 006864), floxed Stat3 (Stat3^fl/fl) mice (Stock 016923) and UBC-GFP (Stock 004353) mice were purchased from Jackson Laboratories. Mfge8^−/− (RBRC01726) mice^{30 (link)} were purchased from RIKEN bioresource research center. Shn3 loxp mice^{31 (link)} were reported previously. All mice were maintained on a C57BL6/J background throughout the study except for experiments involving 4T1.2 cells that were conducted in BALB/cJ mice. All animals were maintained in accordance with the NIH Guide for the Care and Use of Laboratory Animals and were handled according to protocols approved by the Weill Cornell Medical College institutional animal care and use committee (IACUC).

All animal experiments were carried out according to protocols approved by the Institutional Animal Care and Use Committee at Harvard Medical School. Mouse lines are described in published literatures and purchased from the Jackson Laboratory: ShhGFP-Cre (Jackson Laboratory stock no. 005622), Prrx1Cre (Jackson Laboratory stock no. 005584), Sox2CreER (Jackson Laboratory stock no. 017593), tdTMT^tg/+(Rosa26-TdTomato; Jackson Laboratory stock no. 007909), Taz^f/f/Yap^f/f (Jackson Laboratory stock no. 030532), conditional Yap^* or Yap^gof (Rosa26^{lox-stop-lox-rtTA/+};
Col1a1^{Teto-YapS127A/+}) (38 (link)), Ptch1^LacZ (53 (link)), and Ctgf-GFP (38 (link)). Timed mating of heterozygous intercrosses was performed to generate embryos of the indicated embryonic stage. The day in which a vaginal plug was confirmed was designated as E0.5. Mutant and transgenic embryos were processed in parallel with littermate controls. For the ShhCre;Yap^* embryos, Dox was administered to pregnant female mice at 0.2 mg/ml in drinking water starting at E8.5. For Sox2CreER;Yap^* embryos, Dox (same as above) and TM were administered at E7.5 (via intraperitoneal injection of the pregnant females (75 mg/kg of body weight).

All mice were 8–16 weeks of age and maintained on a C57BL/6 background. Prrx1-cre (stock # 005584) recombining in bone marrow mesenchymal cells of the long bones, Lepr^cre (stock # 008320) recombining in bone marrow mesenchymal stromal cells, and Rosa26^LSL-ZsGreen (stock # 007906) mice were obtained from the Jackson Laboratory. Col1a1-cre mice (with 2.3 kb promoter), recombining in mature osteoblasts, were described previously (Liu et al., 2004 (link)). The generation of Thpo^gfp, Thpo^creER, and Thpo^fl mice was described previously (Decker et al., 2018 (link)). Thpo^gfp is a null allele of Thpo. Thpo^creER knockin mice allows tracing of cells that translate THPO protein. All mice were housed in specific pathogen-free, Association for the Assessment and Accreditation of Laboratory Animal Care (AAALAC)-approved facilities at the Columbia University Medical Center. All protocols were approved by the Institute Animal Care and Use Committee of Columbia University.

All the mouse work was carried out following the recommendations by the National Research Council Guide for the Care and Use of Laboratory Animals, with the protocols approved by the Institutional Animal Care and Use Committee of Shanghai, China [SYXK(SH)2011-0112]. ROSA26^fs-tdTomato, Rela^f/f, Krt14-Cre, Prrx1-Cre mouse lines were purchased from The Jackson Laboratory. Theses mice were crossed to B6 mice for at least five times. The young and aged normal mice were on B6 background and maintained at the same facility as the engineered mice.