Faas Laura, Isaacs Harry V
Department of Biology, University of York, York, United Kingdom.
Dev Dyn. 2009 Apr;238(4):835-52. doi: 10.1002/dvdy.21901.
Using Xenopus tropicalis, we present the first analysis of the developmental effects that result from knocking down the function of the three Cdx genes present in the typical vertebrate genome. Knockdowns of individual Cdx genes lead to a similar range of posterior defects; compound Cdx knockdowns result in increasingly severe posterior truncations, accompanied by posterior shifts and reduction of 5' Hox gene expression. We provide evidence that Cdx and Wnt3A genes are components of a positive feedback loop operating in the posterior axis. We show that Cdx function is required during later, but not early stages of development, for correct regional specification of the endoderm and morphogenesis of the gut. Our results support the hypothesis that during amphibian development the overall landscape of Cdx activity in the embryo is more important than the specific function of individual Cdx proteins.
利用热带爪蟾，我们首次分析了典型脊椎动物基因组中三个Cdx基因功能敲低所产生的发育效应。单个Cdx基因的敲低会导致一系列相似的后部缺陷；复合Cdx基因敲低会导致后部截断越来越严重，同时伴有后部移位和5'Hox基因表达减少。我们提供的证据表明，Cdx和Wnt3A基因是在后轴中起作用的正反馈回路的组成部分。我们表明，在发育的后期而非早期阶段，Cdx功能对于内胚层的正确区域特化和肠道形态发生是必需的。我们的结果支持这样一种假说，即在两栖动物发育过程中，胚胎中Cdx活性的整体格局比单个Cdx蛋白的特定功能更为重要。
