Fig. 2

Fig. 2 Zic2a functions primarily in the PT during forebrain development. The effect of Zic2a depletion on overall pattern in the forebrain at Prim-5 was examined using ISH with several markers of forebrain subdivisions (see Supplementary Table 1 for numbers). (B) dlx2a expression is reduced in the PT, but not affected in the telencephalon of zic2a morphants. (C, D) pax6a expression is reduced in the PT region of Zic2a depleted embryos (arrows), but not affected in the telencephalon. (E, F) Expression of emx1, a marker of posterior telencephalon and posterior hypothalamus is expanded in both domains. (G, H) titf1b expression in the hypothalamus is expanded anteriorly in zic2a morphants. (I, J) The thalamus, marked by dbx1a, is formed normally. (K, L) Expression of foxg1 in the telencephalon and shha in the ZLI are normal in zic2a morphants. Note that the AD area, bordered by expression of foxg1 anteriorly and shha posteriorly, is reduced in zic2a morphants. (M) The AD area was measured in pixels² using Axiovision software (Zeiss). The bar graphs represent average AD areas calculated from 12 conMO injected embryos and 18 zic2aMO injected embryos. Standard error bars shown, results significant at p = 0.001. (N) Summary of the effects of Zic2a depletion on forebrain regionalization. The strongest defect is observed in the AD, indicated in red. All embryos are at Prim-5 stage and are shown in lateral views with anterior to the left. Arrows mark the PT and arrowheads mark expanded domains in the telencephalon and hypothalamus. te = telencephalon, th = thalamus, pt = prethalamus, h = hypothalamus.