Figure 3

Analysis of mammary precursor cells and mammary gland formation. (a–c) FACS analysis using CD24-PE, CD49-APC, and CD61-FITC together. The percentages of CD24^MedCD49^High cells in region 1 (R1) (a and c) and CD24^MedCD49^HighCD61⁺ cells (b) are shown. Isotype controls for CD24^MedCD49^High cells are shown in the lower part of panel a. *P<0.05. The profiles from one pair of iPSCs are shown in panels a and b, and the percentages are from the average of five pairs of iPSCs that differed significantly, as indicated in panel c. (d–f) Morphology (d), size (e), and percentage (f) of mammospheres of iPSCs in vitro. *P<0.05. (g) Morphological features of the mammary glands produced in fat pads of nude mice. The boxed areas are enlarged (right). The gland stained by X-gal was formed by the injection of D-ME-iPSCs (derived from Rasa-26 mice). The formation of mammary glands by the injection of D-TF-iPSCs cells was also confirmed using X-gal staining (data not shown). The cleared portion of each mammary fat pad, which contains a lymph node, was stained for whole-mount imaging to confirm that the surgery was successful. The recipient mice were killed 6–8 weeks after implantation, and no tumors were observed in any recipient (n>60). Bars, 1 mm. More than five pairs of independently derived ME-iPSCs and TF-iPSCs were analyzed and similar results were obtained