Figure 2

Pax2 protein expression in the mouse forebrain at E12.5 and E13.5. A-C: Low power views of coronal E12.5 forebrain sections immunoreacted with Pax2; the boxed areas are shown at higher magnification in panels a-c. D: Low power view of a sagittal E12.5 section immunoreacted with Pax2. Note the strong expression of Pax2 in the isthmic region (Is) and the spinal cord (SC), in accordance with previous reports. d, d' higher magnification of the boxed areas in D. A, a, d: Strong Pax2 expression is detected in the septum (Se) of the basal forebrain, mainly in the septal neuroepithelium. A few Pax2-positive cells are detected in the lamina terminalis (LT) (arrows in d). b-c, d': Pax2 is detected in groups of cells found in the lateral hypothalamic area (arrowheads in b and d') and in the anterior hypothalamic neuroepithelium (arrows in b' and d', c). These cell populations might originate from cells located at the base of the hypothalamus (small arrows in b and d'), Pax2 expression can also be seen in the ventral neuroepithelium of the optic recess (asterisk in d'), as previously described. E-G: Low and high power images of E13.5 coronal sections reveal strong Pax2 expression in the septum, mainly in the neuroepithelium (F). A few immunopositive cells are found in the differentiating layer of the septum (G). The boxed areas in the inset panels in E-G indicate the areas shown in the respective high power images. A-C and E-G are sections from the same specimens respectively. Scale bars: D, E-G-insets, 1000 μm; A-C, 500 μm; a, d', F-high power, 200 μm; b-c, d, E, G-high power, 50 μm.