Movie S2.

Cellular behaviors at different stages. (A) Live imaging of cells from a FVB-GFP mouse shows skin sphere formation at stage 2 of culture, with dermal cells moving around an epidermal aggregate. (B) Live imaging of cells from a FVB-GFP mouse shows coalescence of aggregates at stage 3 of culture. (C) Live imaging of cells from a K14-GFP/Lef1-RFP mouse shows Lef1+ cells located adjacent to the K14-GFP+ epidermal basal layer forming a papillary dermal layer. (D) Live imaging of cells from a K14-GFP/Lef1-RFP mouse shows that Lef1+ cells cluster together, forming dermal condensates.