Cd4 cre

Tcf7 conditional mice (Tcf7^{tm1a(EUCOMM)Wtsi}, Institut Clinique de la Souris) were crossed to Flp Deleter (Taconic, 7089), and either CD4-Cre (Lee et al., 2001 (link)) or ERT2-Cre (Seibler et al., 2003 (link)) (Taconic) to generate Tcf7^loxP/loxP; CD4-Cre (cKO) or Tcf7^loxP/loxP; ERT2-Cre (iKO) mice, and to SMARTA transgenic mice, expressing a TCR recognizing the LCMV GP66-77 epitope (Oxenius et al., 1998 (link)). Blimp1-YFP mice (Fooksman et al., 2014 ) were crossed to SMARTA mice. Other mouse strains, in vitro activation, retroviral transduction, flow cytometry, microscopy, RNA and protein analyses, chromatin immunoprecipitation and luciferase assays are described in online supplemental material. For adoptive transfers, 10⁶ (for day 1.5, 2, and 3) or 10⁴ (for other timepoints) SMARTA CD4 T cells were transferred to recipient mice, unless indicated. Mice were intravenously (i.v.) injected with 2×10⁶ (for day 1.5, 2, and 3) or 2×10⁵ (for other timepoints) plaque-forming unit (PFU) of LCMV Armstrong. For ERT2-Cre inducible knockouts, 2mg tamoxifen in corn oil was injected intraperitoneally (i.p.) daily for 3~5 d before LCMV infection. Controls were either Cre⁻ mice or mice transferred with ERT2-Cre⁻ SMARTA injected with Tamoxifen or ERT2-Cre⁺ animals injected with vehicle. All animal husbandry and experiments were approved by the NHGRI or NINDS Animal Use and Care Committees.

C57BL/6J, B10.BR and RAG-1 KO (Rag1^−/−) mice were obtained from The Jackson Laboratory (Bar Harbor, ME). PAG KO (Pag1^−/−) mice, PTPN22 KO (Ptpn22^−/−) mice, Dok-1 KO (Dok1^−/−) mice, mice carrying a conditional allele of SHIP-1 (Inpp5d^fl/fl), and mice lacking c-Cbl and Cbl-b in T cells (Cbl^fl/fl; Cd4-Cre; Cblb^−/−) have been described elsewhere (Davidson et al., 2003 (link); Kitaura et al., 2007 (link); Lindquist et al., 2011 (link); Tarasenko et al., 2007 (link); Yang and Seed, 2003 (link)). Mice expressing the Cre recombinase under the control of the CD4 promoter (Cd4-Cre) were from Taconic (Hudson, NY). Transgenic mice expressing class II MHC-restricted TCR OT-II or AND were also reported (Barnden et al., 1998 (link); Kaye et al., 1989 (link)). All mice were maintained in the C57BL/6 background. Littermates were used as controls in all experiments. Animal experimentation was done in accordance to the Canadian Council of Animal Care and approved by the IRCM Animal Care Committee.

Cd4^tm2Litt (Cd4(0.4k)⁻, Δ0.4kb) and Cd4^tm1Yzo (Cd4(1.5k)^F) alleles were described previously (11 (link), 13 (link)). These alleles were backcrossed 12 generations to the C57BL6 (B6) background before intercrossing or crossing to Cre transgenic lines. Cd4^tm1Yzo was bred to Cd4-cre (Taconic) (14 (link)) to delete the 1.5 kb genomic fragment encompassing the silencer and DHS+3 (Δ1.5kb), or Vav1-cre (Jackson Laboratory) (15 (link)) for data shown in Supplementary Fig. 3. Mice homozygous for the Cd4^tm2Litt or Cd4^tm1Yzo were used all experiments. C57BL6 mice (National Cancer Institutes, Frederic, MD) were used as wild-type control. Bone marrow chimeras were generated by intravenous transfer of bone marrow cells (5 × 10⁶ cells) into lethally irradiated B2m^−/− mice (16 (link)) purchased from Jackson Laboratory. The recipient mice were treated with Trimethoprim and Sulfamethoxazole for four weeks and analyzed twelve weeks after transplantation. All mice were housed in a specific pathogen free animal facility at Washington University School of Medicine and experiments were performed according to a protocol approved by the Animal Studies Committee at Washington University in St. Louis.