Fig. 9
ERα mRNA and protein expression ERα−/− and WT MECs. a ERα immunofluorescence (red) and b RNAscope with anti-Esr1 probes (red) on an adjacent section counterstained with DAPI (blue) on mammary gland from 6-week-old WT female. Scale bars; 50 μm. c Bar plot showing percentage of luminal cells with detectable levels of ERα protein and Esr1 mRNA at puberty (n = 5; mean ± SD). d Bar plot showing percentage of luminal cells with different Esr1 RNAscope scores (n = 5; mean ± SD). e RNAscope with anti-Areg probes (red) counterstained with DAPI (blue) on mammary gland from 6-week-old WT female. Scale bar; 50 μm. f RNAscope with anti-Esr1 or g anti-Areg probes (red) co-stained with anti-PgR antibody (green) and counterstained with DAPI (blue). Arrowheads point to apically-located luminal cells with ERα transcript but no PgR expression (f) and Areg transcript and PgR expression (g). Empty arrowheads point to myoepithelial cells f, g. Scale bars; 100 μm. h Current model of mammary stem cells and the differentiation hierarchy after Visvader, J.E. and Stingl, J.56. In grey: previously proposed ERα status of different MEC differentiation stages. In red: ERα status based on the present findings
