Amacher Sharon L, Draper Bruce W, Summers Brian R, Kimmel Charles B
Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA.
Development. 2002 Jul;129(14):3311-23. doi: 10.1242/dev.129.14.3311.
T-box genes encode transcriptional regulators that control many aspects of embryonic development. Here, we demonstrate that the mesodermally expressed zebrafish spadetail (spt)/VegT and no tail (ntl)/Brachyury T-box genes are semi-redundantly and cell-autonomously required for formation of all trunk and tail mesoderm. Despite the lack of posterior mesoderm in spt(-);ntl(-) embryos, dorsal-ventral neural tube patterning is relatively normal, with the notable exception that posterior medial floor plate is completely absent. This contrasts sharply with observations in single mutants, as mutations singly in ntl or spt enhance posterior medial floor plate development. We find that ntl function is required to repress medial floor plate and promote notochord fate in cells of the wild-type notochord domain and that spt and ntl together are required non cell-autonomously for medial floor plate formation, suggesting that an inducing signal present in wild-type mesoderm is lacking in spt(-);ntl(-) embryos.
T-box基因编码控制胚胎发育多个方面的转录调节因子。在此，我们证明中胚层表达的斑马鱼spadetail（spt）/VegT和no tail（ntl）/Brachyury T-box基因对于所有躯干和尾部中胚层的形成是半冗余且细胞自主所需的。尽管在spt（-）；ntl（-）胚胎中缺乏后中胚层，但背腹神经管模式相对正常，唯一显著的例外是后内侧底板完全缺失。这与在单个突变体中的观察结果形成鲜明对比，因为单独的ntl或spt突变会增强后内侧底板的发育。我们发现，ntl功能对于抑制野生型脊索区域细胞中的内侧底板并促进脊索命运是必需的，并且spt和ntl共同对于内侧底板的形成是非细胞自主必需的，这表明spt（-）；ntl（-）胚胎中缺乏野生型中胚层中存在的诱导信号。
