Figure 2: Dnmt1 is indispensable for mammary stem/progenitor cell maintenance.

(a) Single-cell suspensions from mammary glands of Dnmt1^fl/fl and Dnmt1^Δ/Δ mice were stained with CD24, CD49f and Lin (CD31, CD45 and CD119) antibodies. Representative FACS dot blots showing reduced stem (Lin⁻CD49f^highCD24⁺) and luminal cells (Lin⁻CD49f^lowCD24⁺) in Dnmt1-knockout mice (n=3–5 mice in each). Bar diagram represents per cent of total stem and luminal cell populations in the respective mammary glands. (b) Similarly, single-cell suspensions from mammary glands of Dnmt1^fl/fl and Dnmt1^Δ/Δ mice were stained with CD61, CD49f and Lin antibodies. Representative contour blots show reduced luminal progenitor cells (Lin⁻CD49f^lowCD61⁺) in Dnmt1-knockout mice. Bar diagram represents per cent of total ER⁺ and ER⁻ cell populations in the respective mammary glands. (c) Representative images show a decrease in size and number in mammospheres generated with cells from Dnmt1^Δ/Δ mice compared with cells from Dnmt1^fl/fl mice (n=3–5). Twenty thousand cells per ml were used in each group. Bar diagram represents total number of mammospheres per 20,000 cells. Scale bar, 100 μm. Data are representative of five independent mice per group. Statistical analysis was performed using unpaired Student’s t-tests. Error bars represent s.e.m. of independent experiments.