Supplementary Figure 1: Gating strategy for flow cytometry analysis.

a-g, Unicellular suspension of skin and mammary bud cells from Lgr5-IRES-GFP E14 embryos stained for Lin (CD31, CD45, CD140a) in APC and CD49f in PE were gated as shown in a to eliminate debris, doublets were discarded with gate shown in b followed by gate showed in c, the living cells were gated by DAPI dye exclusion as shown in d, the non-epithelial Lin positive cells were discarded in e. The CD49f Hi cells were gated as shown in f and the GFP + cells were gated as shown in g. h-o, Unicellular suspension of mammary cells from adult K8rtTA/TetOCre/ΔNp63-IRES-GFP, induced at P30 and analyzed at P45, stained for Lin (CD31, CD45, CD140a) in PE, CD24 in PECy7 and CD29 in APC, were gated as shown in h to eliminate debris, doublets were discarded with gates shown in i followed by gate shown in j, the living cells were gated by DAPI dye exclusion as shown in k, the non-epithelial Lin positive cells were discarded in L and the GFP + cells were gated as shown in m. CD24 and CD29 expression was studied in Lin- cells (n) or in YFP + cells (o). The CD24 + CD29Lo gate corresponds to luminal cells (LC), while CD24 + CD29Hi gate corresponds to basal cells (BC). The stromal population corresponds to the cells labelled due to the leakiness of the Tet-O-Cre, as described previously in reference 14.