Conditional Knockout mESC Generation

The Rosa26^Cre-ERT2/+; Taf8^flox/flox mouse embryonic stem cells (mESCs) were generated previously by F. El Saafin^{21 (link)}. Briefly, mice carrying the Taf8^lox allele were bred to mice carrying the Rosa26^Cre-ERT2 allele to produce Rosa26^Cre-ERT2/+;Taf8^flox/flox E3.5 blastocysts and to isolate Rosa26^Cre-ERT2/+;Taf8^flox/flox mouse embryonic stem cells (mESCs)^{21 (link)}. The Rosa26^Cre-ERT2/R;Taf10^flox/flox mESCs were generated previously by P. Bardot^{20 (link)}. Briefly, the ESCs were derived from Rosa26^Cre-ERT2/R;Taf10^lox/lox E3.5 blastocysts^{20 (link)}. mESCs were cultured in DMEM (4.5 g/l glucose) with 2 mM Glutamax-I, 15% ESQ FBS (Gibco), penicillin, streptomycine, 0.1 mM non-essential amino acids, 0.1% ß-mercaptoethanol, 1500 U/mL LIF and two inhibitors (2i; 3 µM CHIR99021 and 1 µM PD0325901, Axon MedChem) on gelatin-coated plates. To induce deletion of Taf8, mESCs were treated with 0.5 µM 4-OH tamoxifen (Sigma) for 5–6 days, and to induce deletion of Taf10, Rosa26^Cre-ERT2/R;Taf10^lox/lox mESCs were treated for 4 days with 0.1 µM 4-OH tamoxifen (Sigma). The above-described mESCs have already been described^{20 (link),21 (link)} and were derived according to animal welfare regulations and guidelines of the French Ministry of Agriculture and French Ministry of Higher Education and Research, and the Australian Animal Welfare Committee, respectively.