Identification of CD14+ and CD61+ cells in the luminal ER- population and confirmation of differential expression of transcriptional regulators. A) Flow cytometric analysis of virgin mouse mammary cells stained with anti-CD24 and a control IgG or anti-CD24 and anti-Sca-1, to define the myoepithelial/basal, luminal ER- and luminal ER+ populations. The staining patterns of the three populations with control IgGs or anti-CD14 and anti-CD61 is indicated. The percentages in the CD14/CD61 quadrants indicate the mean percentage (± SD; n = three independent sorts) of that epithelial subpopulation (not of the total epithelium) falling into that quadrant. B) qPCR analysis of expression of transcriptional regulators in mammary epithelial subpopulations. Mean gene expression levels ± 95% confidence limits for the seventeen transcriptional factors indicated on the X-axis are given relative to the basal/myoepithelial population. The genes are grouped according to the cell population(s) which has the strongest level of expression. If there is no data point for a population for a given gene, then that gene could not be detected in that population.