Fig. 2. Depletion of maternal Zic2. (A) Dose-dependent depletion of Zic2 from oocytes of two different donor females. Oligo 10MP was injected at the indicated doses and oocytes were cultured for 24 hours before analysis by RT-PCR. Samples were quantitated relative to uninjected oocytes (Un) from female 1 (black bar). (B) Zic2 is the only Zic gene expressed maternally. RT-PCR of Zic1, Zic2, Zic3 and Zic5 expression in stage 10.5 embryos (Em; stage 14 for Zic5), stage VI oocytes (WO) or animal and vegetal halves of oocytes (An and Vg). (C,D) Representative phenotypes of uninjected (C) and Zic2-depleted (D) embryos at stage 38/39. (E,F) Zygotic Zic2 is expressed in maternal Zic2-depleted embryos. (E) Whole-mount in situ hybridization of Zic2 expression in stage 18 uninjected (two lower left embryos) and maternal Zic2-depleted embryos (three upper right). Although neural tube formation is delayed, Zic2 is expressed anteriorly and at the neural plate border. (F) Gastrula stage series of Zic2 expression in uninjected and Zic2-depleted embryos. (G) Histological sections of embryos from C,D taken through the head (upper panel) or just behind the level of the otic vesicle (lower panel). In each panel, the uninjected embryo is on the left and the Zic2-depleted embryo is on the right. The arrow indicates a duplicated notochord. (H) Real-time RT-PCR analysis of neural markers in control and Zic2-embryos. Relative expression values were normalized to ODC and expressed as a percentage of a stage 22 embryo.