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Fig. 9.
RA and ERF/ETV3L action in primary neurogenesis. The mutual inhibitory interactions between FGF and RAR signaling have been discussed in this paper and elsewhere (Diez del Corral and Storey, 2004; Moreno and Kintner, 2004). FGF signaling and BMP inhibition (required for neural induction) leads to the upregulation of neural progenitor and pro-proliferation genes such as Zic1, Zic3, Foxd4l1 and Geminin. RA upregulates ETS repressors Erf and Etv3l, which function to inhibit these genes and to promote neuronal differentiation. Loss of either ERF or ETV3L leads to expansion of Geminin and loss of N-Tubulin on the injected side of the embryo. Embryos are shown in dorsal view at stage 14; anterior is on the right. |
