Fig. 3

Single cell transcriptomes of terminal end buds and subtending mammary ducts in puberty. a Schematic diagram of the structure of the terminal end bud (TEB) that characterizes the ductal tree during puberty. b t-SNE and ternary plots of the integrated scRNA-seq transcriptomes of epithelial cells from microdissected TEBs and subtending ducts colored by cell cluster (n = 3 Ecadherin-GFP mice). Ternary plot positions the cells by expression of known lineage signature genes as described above. c Same t-SNE and ternary plots as in b but colored by cellular structure: TEBs (blue) and ducts (yellow). d Same t-SNE plot as in b and c but colored by basal, LP and ML signature scores. The cells marked with a dotted circle express both LP and ML signatures and match the intermediate LP-ML subset visible in the ternary plot in b. e t-SNE expression plots for typical epithelial markers and the proliferation marker Mki67. f Heatmap showing relative expression for 164 genes DE between TEB (blue) vs ductal (yellow) cells in the basal compartment. Red = high expression; blue = low expression. g Co-immunofluorescence labeling of sections from 5-week-old glands (TEBs and ducts) for expression of Keratin K8/K18 (green), Mylk, or Myh11 (pink). DAPI is shown in gray. Scale bars, 20 μm