GSE210594
Positional cues underlie cell fate specification during branching morphogenesis of the embryonic mammary epithelium
By single-cell RNA-sequencing across 4 stages of embryonic development, we reconstructed the differentiation trajectories of multipotent mammary stem cells towards basal and luminal fate. Our data revealed that MaSCs can already be resolved into distinct populations exhibiting lineage commitment at the time coinciding with the first sprouting events of mammary branching morphogenesis (E15.5). Through an interactive web tool for the visualization of gene expression across our developmental atlas, we provide novel molecular markers for committed and multipotent MaSCs, and define their spatial distribution within the developing tissue. Furthermore, we show that the mammary embryonic mesenchyme is composed of two spatially-restricted cell populations, representing the sub-epithelial and dermal mesenchyme. Overall design: Embryonic mammary gland cells were isolated by Fluorescence-activated cell sorting (FACS) according to the presence or absence of EpCAM signal (epithelial or mesenchymal cells, respectively) and analyzed by scRNAseq using the 10x Chromium system.