FIGURE 1.

GnT-Vb is specifically and highly expressed in the developing and adult nervous system. In situ hybridization analyses were conducted on embryos and adult brains to determine the timing and localization of GnT-Vb mRNA. GnT-Vb expression was first detected at embryonic day (E) 7.5 (data not shown), but at all time points it was found almost exclusively within the nervous system. Expression was detected specifically in the nervous system of embryos at E9 (A), E11 (B), and E13 (C). At E15 the expression of GnT-Vb message is shown (D) and the same section was then Nissl-stained (E) to demonstrate the specific localization of GnT-Vb mRNA in neural tissue. F–H, brains from an E15 mouse was removed and sliced horizontally to investigate the spatial distribution of GnT-Vb in the brain. GnT-Vb mRNA (F) and fluorescent Nissl stain (G) of the same section were overlaid (H) to show that GnT-Vb is highly expressed in the subventricular zone (SVZ) and intermediate zone (IZ) and more sparsely in the marginal zone and cortical plate (MZ/CP). It is largely absent from the ventricular zone (VZ). Adult brains were sectioned parasagittally to investigate the spatial distribution of GnT-Vb (I and J) and GnT-V (K). GnT-Vb is highly expressed in the inferior colliculus (IC), nuclei in the thalamus (Thal), the rostral migratory stream (RMS), the dentate gyrus (DG), CA fields of the hippocampus (CA), the striatum and superficial layers of the cortex (I and J). In contrast GnT-V is more broadly expressed throughout the brain although it is largely absent from the striatum (K).