Fig. 1.

Expression of laminin α chain isoforms in the mammary gland is cell type-specific. (A) Representative images of RNA ISH performed with probes for Lama1, 3, 4 and 5 on TEBs of 7-week-old pubertal mammary glands. (B) Representative images of RNA ISH of mammary glands from embryonic day 13.5 pregnant mice performed with probes for Lama1 and 5 on TEBs. (C) Representative images of Lama5 RNA ISH coupled with either K8 or K14 antibody staining. Asterisk denotes background staining. The dashed boxes indicate the magnified regions in the lower panels. (D) Quantification of the percentage of K14⁺ or K8⁺ cells showing either Lama1 or Lama5 expression. Lama1 quantification in K14⁺ and K8⁺ cells (K14, n=23 ducts; K8, n=28 ducts; from three animals). Lama5 quantification in K14⁺ (n=29) and K8⁺ cells (n=31) ducts from three animals. Data points correspond to individual ducts analyzed. (E) qRT-PCR analysis of Lama5 expression compared with GAPDH in populations of stromal (St), basal (B), luminal HR⁺ and luminal HR⁻ cells FACS sorted from mammary glands (St, n=3; B, n=4; HR⁺, n=5; HR⁻, n=4 mice analyzed). Data are mean±s.d. An unpaired two-tailed Student's t-test was used to compare indicated groups (*P<0.05, **P<0.01, ****P<0.0001). Scale bars: 50 µm (A); 50 µm (B); 20 µm.