Schematic diagram showing the lineage-tracing strategy of Bcl11b + cells from puberty for experiments in b - i. Bcl11b-rtTA (+, +) TetO-Cre (+) tdTomato (+, +) female mice were administered with 2 mg doxycycline intraperitoneally for three consecutive days at 4-week-old, and then mated during adult stage for multi-pregnancy. Mammary glands at various time points as indicated during multiple pregnancies (1 st Preg17.5 d, 2 nd Preg17.5 d, 3 rd Preg17.5 d) were harvested for tdTomato labeling analysis.
