FIG. 2.

Distinct neuronal cell populations express βGeo in the adult Rosa3 brain. Brains were harvested from adult R3/+ mice and processed as described for Fig. 1. (A) Hippocampus. Intense staining is present in the CA1 pyramidal neurons (pyr [arrow]), and light staining is present in the CA3 pyramidal cells. Light staining to no staining is visible in the CA2 neurons, the oriens layer (ol), and the stratum radiatum (sr). Only diffuse staining is present in the dentate gyrus. ml-D, molecular layer; gl-D, granular layer; pl-D, polymorphic layer. (B) Cerebral cortex. Variable staining is present in the cerebrum. The molecular layer (ml-C), which is comprised mainly of nerve fibers, is unstained. Although cortical layers II to VI (II-VI-C) are not clearly discernible, the majority of stained neurons are present in the external granular layer (egl). (C) Cerebellum. Purkinje cells are strongly stained (pc [arrow]), but only sparse staining is present in the granular layer (gl). Stellate cells (sc [arrow]) of the molecular layer (ml) are unstained. nf, nerve fibers. (D) Striatum. Some neurons making up the gray matter (gm) of the striatum are stained. nf, nerve fiber bundles. (E) Inferior colliculus. Staining is present in cells throughout the external cortex of the inferior colliculus (ec-IC) adjacent to the cerebellum. gl, granular layer; ml, molecular layer of the cerebellum. (F) Choroid plexus. Intense staining is evident in the epithelial cells of the choroid plexus (CP) forming the roof of the fourth ventricle. Stained cells are present throughout the vestibular nucleus of the medulla oblongata (vn-MO) region. Nuclear fast red was used for counterstaining. Bar (in panel D) for panels A to D, 75 μm. Bar (in panel F) for panels E and F, 125 μm.