The Co-factor of LIM Domains (CLIM/LDB/NLI) Maintains Basal Mammary Epithelial Stem Cells and Promotes Breast Tumorigenesis
Figure 1
Clims promote branching morphogenesis and proliferation.
(A) Clim2 mRNA is predominantly expressed over Clim1 throughout mammary gland development. Gene expression is normalized to 18s mRNA. (B–C) IHC showing expression of Clim2 in the (B) TEB and (C) duct in mammary glands from 6 week old mice. Clim2 expression is observed in basal and luminal cells, with slightly higher expression in basal cells. (D) IHC detecting the Myc-tag of DN-Clim demonstrates expression in the K14-positive basal layer of mammary glands from 6 week old mice. (E) Whole mount analysis of mammary glands throughout branching morphogenesis and pregnancy demonstrates defective branching morphogenesis and TEB maintenance in DN-Clim mammary glands. Images are representative of at least three mice per time point. (F) Mean ductal penetration of the three longest ducts throughout branching morphogenesis indicates a delay in DN-Clim ductal penetration. Data are normalized using the center of the lymph node as the central reference point. P-value derived from repeated measures ANOVA. (G) Mean number of branch points for the three longest ducts normalized to the length of the duct (mm) indicates reduced branching frequency in DN-Clim mammary glands. ** P-value<0.01 determined by Student's t-test. (H) TEB diameter (µm) is reduced in DN-Clim mammary glands throughout branching morphogenesis. P-value derived from repeated measures ANOVA. (I) Proportion of pregnancy stage mammary fat pad filled with epithelial tissue demonstrates a reduced epithelial density in DN-Clim mammary glands. ** p-value<0.01 determined by Student's t-test. (J) Proportion of BrdU positive cells in TEB (cap and body cells) and duct cells is reduced in DN-Clim mammary glands. Representative images of the TEB are shown. *** p-value<0.01 determined by Student's t-test. Quantification for A, F-J represent mean ± SEM for at least three mice.