Figure 3.

Histochemical (A–J) and immunocytochemical (K–O) demonstration of transgene expression in brain and peripheral tissues of A108.2 transgenic mice. (A) Complete coronal slice of brain showing lacZ expression in the SCN and in the medial habenula (MHb). Cells positive for lacZ (B) in the glomerular and internal granular layers of the olfactory bulb, (C) in the lateral septum, (D) in a small number of cells in the medial preoptic area (MPO) and in the supraoptic nuclei (SON), (E) in the SCN, (F) in the ependymal cell layer of the rostral portion of the third ventricle (III) and in the walls of numerous blood vessels (arrowed), (G) in the ependymal cell layer of the fourth ventricle (IV), (H) in a slice of the brain that includes both the midbrain and the caudal portion of the forebrain, showing strong expression of lacZ in the walls of the major cerebral blood vessels, (I) in the pancreas of a transgenic (tg), but not of a wild-type (wt) mouse, and (J) in the spleen of a transgenic (tg), but not of a wild-type (wt) mouse. β-galactosidase-like immunoreactivity (K) in cells and processes in the SCN and (L) in the medial habenular nucleus. HA-like immunoreactivity (M and N) in the medial habenular nucleus; the membrane-associated immunoreactivity for this antigen is clearly seen in some cases (arrowed). Labeling was absent (O) when the antiserum had been preincubated with excess HA peptide. lv, lateral ventricle; Aq, aqueduct; LSi, intermediate portion of the lateral septal nucleus; LSv, ventral portion of the lateral septal nucleus; ox, optic chiasm.