Expression of Siamois and Twin in the blastula Chordin/Noggin signaling center is required for brain formation in Xenopus laevis embryos
Expression of Siamois and Twin in the blastula Chordin/Noggin signaling center is required for brain formation in Xenopus laevis embryos
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DOI：
10.1016/j.mod.2007.10.005
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发表时间：
2008-01-01
影响因子：
2.6
通讯作者：
Kuroda, Hiroki
中科院分区：
文献类型：
--
作者：
Ishibashi, Hideyuki;Matsumura, Noriko;Kuroda, Hiroki
囊胚Chordin和Noggin表达（BCNE）中心位于爪蟾囊胚胚胎的背侧动物区域，包含预期的前神经外胚层和Spemann组织者前体细胞。在这里，我们表明，与以前的报告相反，典型的Wnt靶同源异型盒基因，在非洲爪蟾中使用反义吗啉双敲低这些基因阻断头部形成，减少其他BCNE中心基因的表达，上调Bmp 4表达，并通过氯化锂消除hyperdorsalization。此外，获得和丧失功能的实验表明，Siamois和Twin的表达被植物转录因子VegT抑制。我们认为VegT表达导致母体β-连环蛋白信号将Siamois和Twin表达限制在BCNE区域。头部形成需要Siamois和Twin对BMP信号的两步抑制-首先通过Bmp 4的转录抑制，然后通过BCNE中心中BMP抑制剂Chordin和Noggin的表达的激活。(c)2007爱思唯尔爱尔兰有限公司保留所有权利。
The blastula Chordin- and Noggin-expressing (BCNE) center located in the dorsal animal region of the Xenopus blastula embryo contains both prospective anterior neuroectoderm and Spemann organizer precursor cells. Here we show that, contrary to previous reports, the canonical Wnt target homeobox genes, Double knockdown of these genes using antisense morpholinos in Xenopus laevis blocked head formation, reduced the expression of the other BCNE center genes, upregulated Bmp4 expression, and nullified hyperdorsalization by lithium chloride. Moreover, gain- and loss-of-function experiments showed that Siamois and Twin expression is repressed by the vegetal transcription factor VegT. We propose that VegT expression causes maternal beta-Catenin signals to restrict Siamois and Twin expression to the BCNE region. A two-step inhibition of BMP signals by Siamois and Twin - first by transcriptional repression of Bmp4 and then by activation of the expression of the BMP inhibitors Chordin and Noggin-in the BCNE center is required for head formation. (c) 2007 Elsevier Ireland Ltd. All rights reserved.