Figure 4.

The pharmacological inhibitor GI254023X does not cause gross defects in the patterning of the diencephalic neuroepithelium. Neuroepithelial marker immunostaining of 12 μm cross sections of the diencephalon/midbrain regions of stage 40 embryos exposed at stage 33/34 to either 0.05% DMSO control medium (A, C, E, G) or 5 μm GI254023X (B, D, F, H). In all panels, the exposed side of the brain is on the left, and the unexposed side is on the right. Arrowheads point to the dorsal and ventral midline. Representative images are shown for the ventrally expressed transcription factor, Islet-1 (A, B), general neuronal markers NCAM (C, D) and Zn-12 (E, F), and the neurotransmitter GABA, which is expressed in three dorsal-to-ventral arrayed populations of neurons in the diencephalon (G, H, asterisk). No gross alterations in the pattern of expression of the antigens were observed between control and inhibitor-treated brains. Ex, Exposed side of brain; UnEx, unexposed side of brain; Ve, ventricle; Di, diencephalon; E, eye; np, neuropil; D, dorsal; V, ventral. Scale bar, 100 μm.