Fig. 1

Mammary luminal progenitors express Met and Trp53. a Flow cytometry analysis of CD24 and ICAM-1 expression in mammary cells isolated from adult virgin mice. The gated subsets within the CD24⁺ epithelial cell pool include CD24⁺ ICAM1⁺ basal cells (Ba), CD24⁺ ICAM1⁻ and CD24⁺ ICAM1⁺ luminal cells (Lu-neg and Lu-pos, respectively). b Heat map showing expression of the major luminal-specific genes discriminating the hormone-sensing Lu-neg cell population from the clonogenic Lu-pos cell subset separated by ICAM-1. The mean fold-changes in gene expression vary from 1.8 (Wnt4) to 6.0 (Elf5). c Gene expression level of Met and Trp53 in isolated Lu-neg and Lu-pos cells, evaluated by qPCR. Data are the mean ± SEM of 4 separate cell preparations. *p ≤ 0.05, **p ≤ 0.01. d Heat map showing the upregulated expression of Trp53- and p53-activated target genes in the Lu-pos cell samples. Sixty-eight percent of the genes display a differential expression with a mean fold-change higher than 1.7. e Validation of the array data shown in d by qPCR analysis. Results are shown as mean ratios (± SEM) between gene expression levels in Lu-pos and Lu-neg cells from at least 3 separate preparations. All the tested genes were significantly overexpressed in Lu-pos compared to Lu-neg cells by at least a factor 2 (p ≤ 0.01)