Tg mmtv cre 4mam j

All mouse experiments were carried out at Baylor College of Medicine (BCM) and The Hospital for Sick Children with the approval of their respective Institutional Animal Care and Use Committees. All mice were housed in a pathogen-free facility. Mouse lines included: Gt(ROSA)26Sor^tm1Jus – ‘R26PR’ (Carofino et al., 2013 (link)), Gt(ROSA)26Sor^tm2Jus – ‘R26FLPR’ (both generated by Justice Laboratory), Tg(MMTV-cre)4Mam/J – ‘MMTV-cre’ (The Jackson Laboratory, Bar Harbor, Maine, US), Tg(Mx1-cre)1Cgn/J – ‘Mx1-cre’ (from Dr Margaret A. Goodell, Baylor College of Medicine, Houston, Texas, US), and Rag1^tm1Mom/J – ‘Rag1^−/−’ (from Dr David Corry, Baylor College of Medicine, Houston, Texas, US). All lines were on a C57BL/6 (J or N) background, with the exception of MMTV-cre (B6.129 F1 hybrid). The R26FLPR line was generated as previously described (Carofino et al., 2013 (link)), except for the addition of an N-terminal FLAG tag and the addition of P2A-eGFP rather than IRES-eGFP. P2A-eGFP was amplified from OCT4-2A-eGFP-PGK-Puro, which was a gift from Rudolf Jaenisch (Addgene plasmid # 31938). Mx1-cre was activated in both the R26PR;Mx1-cre and R26FLPR;Mx1-cre lines via intraperitoneal injection of 250 µg polyinosinic:polycytidylic acid (pIpC) (Sigma-Aldrich), with three doses spaced two days apart and one dose, respectively, at 8 weeks of age.

The Cre-regulated CRTC1-MAML2 transgenic mice were crossed with homozygous transgenic MMTV-Cre mice (Tg[MMTV-cre]4Mam/J, 003553, The Jackson Laboratory) to induce expression of the CRTC1-MAML2 fusion transgene in salivary gland. Mice carrying the fusion transgene were identified by PCR as described above. Nontransgenic littermates were used as negative controls.
The Cre-regulated CRTC1-MAML2 transgenic mice were also crossed with the Dcpp1tm1.1 (cre/ERT2)Ovi (028731, Jackson Laboratory; designated as “dCre-ERT2”), and Piptm1.1(cre/ERT2)Ovi (023201, Jackson Laboratory; designated as “pCre-ERT2”). dCre-ERT2 is a tamoxifen–inducible (TAM-inducible) Cre strain in which a fusion of Cre to a mutant form of human estrogen receptor (ERT2) was inserted right after the initiation ATG codon of Dcpp1 exon 1, and its TAM-induced Cre expression was specific to sublingual serous demilune cells and intercalated duct cells in parotid glands (38 (link)). pCre-ERT2 is a TAM-inducible Cre strain in which exon 1 of Pip gene is replaced by Cre-ERT2 fusion, and its TAM-induced Cre expression was specific to acinar cells in submandibular glands (38 (link)). TAM (75 mg/kg body weight) was i.p. injected to mice at about 4 weeks of age once daily for 3 consecutive days.