Figure 1: Identification and functional characterization of Id4-positive MECs.
From: ID4 controls mammary stem cells and marks breast cancers with a stem cell-like phenotype
(a) Id4 and cytokeratin 8 (CK8) expression detected by immunofluorescence in terminal end buds (upper panels) and mature ducts (lower panels) of 8-week-old wild-type mice. Scale bars, 20 μm. Representative image from five animals analysed. (b) Id4GFP reporter activity in MEC subsets identified by CD24, CD29 and CD61 immunostaining and flow cytometry. Representative histograms from five independent experiments. (c) Sorted CD29hi/GFPhi and CD29hi/GFPlo mammary epithelium from Id4GFP/+ mice were transplanted at two doses (100 and 500 cells) into the cleared mammary fat pad of naive FVB/N mice (seven glands per group) and analysed by whole-mount histology 8 weeks later. Percentage of transplanted mammary glands that showed a positive engraftment indicated below. Scale bars, 1 mm. (d) Single-cell RT–PCR for Id4 and MEC differentiation markers in Id4hi (top quartile; red) and Id4lo (bottom quartile; green) cells. All genes with significantly altered expression are shown with P value (ANOVA). * Indicates a negative correlation.
