Fig. 3.

Loss of Lkb1 in the mouse mammary gland results in hyperbranching, deterioration of BM, and disruption of apical polarity. (A) Carmine-alum staining of mammary gland whole mounts from virgin and parous control and W-Cre;Lkb1^lox/lox mice shows ductal hyperbranching. (Scale bars: 1 mm; close-up images, 500 μm.) (B) H&E-stained paraffin sections of virgin and parous W-Cre;Lkb1^lox/lox glands show eosinophilic thickenings (arrowheads). (Scale bar: 100 μm.) (C) Collagen IV and I immunostaining of paraffin sections of parous W-Cre;Lkb1^lox/lox glands. (Scale bar: 50 μm.) (Insets) Black line delineates pattern of Collagen IV staining. (D) Carmine-alum–stained mammary gland whole mounts and H&E-stained paraffin sections of genetically engineered ductal trees expressing either shControl or shLkb1-1 construct. (Scale bar: 1 mm.) Close-up images (cropped from the original image) show ductal side branching (59.6 branch points in the shControl and 71.3 branch points in shLkb1 counted as in Fig. S3C from 4 animals per group, 3–4 image fields per sample with a magnification of 40×). (Scale bar: 200 μm.) (E) Collagen IV and I immunostaining of paraffin sections of shControl and shLkb1-1–expressing glands. (Scale bar: 50 μm.) (Inset) Black line delineates pattern of Collagen IV staining. (F) Parous control and W-Cre;Lkb1^lox/lox glands immunostained for Occludin and ZO-1. Asterisks mark the lumens. (Scale bar: 20 μm.)