FIG. 1.

β-Galactosidase expression is widespread in the adult ROSA3 mouse. X-Gal staining was used to determine the βGeo expression patterns in frozen sections of various tissues harvested from adult R3/+ mice. Each panel is a micrograph taken at ×100 magnification. (A) Intestine. Epithelial cells (ep) lining the villi, which are seen mostly in cross section, are strongly and uniformly stained. No staining is detected in the lamina propria (lp), which form the cores of the villi, or in the circular and longitudinal muscles forming the muscular coat (mc) surrounding the intestine. (B) Kidney. Staining is present in the convoluted tubules of the renal cortex (rc) and absent from the renal medulla (rm). Glomeruli (gm) are less intensely stained. (C) Spleen. Staining is mostly restricted to cells in the marginal zone (mz) surrounding splenic nodules (sn). (D) Liver. Sparse staining is mainly detected in hepatocytes of the hepatic cords (hc). Vascular endothelial cells forming hepatic blood vessels (v) are unstained. (E) Thyroid. Intense staining is present in follicle cells of the pyramidal lobe (pl). In an adjacent lobe, follicular cells are lightly stained whereas presumptive parafollicular cells (pf) are intensely stained. (F) Lung. Intense staining is present in the columnar epithelium of the bronchioles (br) and in a population of (type II) alveolar cells (ac) lining alveoli and alveolar sacs (as). No staining is detected in smooth muscle (sm) surrounding the bronchioles and blood vessels (arrows). (G) Skin. Intense labeling is present in the sebaceous glands (sg) of each hair follicle. Some label is detected in the cells of the epidermal (el) and dermal layers (dl). Fat cells (fc) underlying the dermis also appear labeled. (H and I) Skeletal muscle (H) and cardiac muscle (I). No staining is detected in muscle cell bundles (mb) or cardiac muscle cells (cm). Cells comprising connective tissue (ct) appear to be lightly or negatively stained. Eosin was used for counterstaining.