Interaction of Wnt and caudal-related genes in zebrafish posterior body formation
Interaction of Wnt and caudal-related genes in zebrafish posterior body formation
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DOI：
10.1016/j.ydbio.2004.12.007
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发表时间：
2005-03-01
影响因子：
2.7
通讯作者：
Hibi, M
中科院分区：
文献类型：
--
作者：
Shimizu, T;Bae, YK;Hibi, M
虽然Wnt信号在早期脊椎动物胚胎发育的身体模式中起着重要作用，但Wnt控制身体模式的个体过程的机制在很大程度上是未知的。在斑马鱼中，wnt 3a和wnt 8在胚盘边缘的重叠区域中表达，随后在尾芽中表达。联合抑制Wnt 3a和Wnt 8的反义吗啉寡核苷酸导致anteriorization的神经外胚层，扩大的背组织者，和损失的后体结构-一个更严重的表型比每个Wnt单独抑制-表明一个多余的作用Wnt 3a和Wnt 8。腹侧表达的同源异型盒基因vox、vent和ved介导Wnt 3a/Wnt 8信号传导以限制组织者结构域。在wnt 3a/wnt 8变形体胚胎中，尾部相关cdx 1a和cdx 4/kugelig的表达强烈降低，但bmps和cyclops的表达没有降低。与wnt 3a/wnt 8变形胚胎一样，cdx 1a/cdx 4变形胚胎显示尾部结构完全丧失，表明Cdx 1a和Cdx 4介导Wnt依赖的后体形成。我们还发现cdx 1a和cdx 4的表达依赖于Fgf信号。hoxa 9a和hoxb 7a的表达在wnt 3a/wnt 8和cdx 1a/cdx 4变形胚胎中以及在Fgf信号传导缺陷的胚胎中下调。Cdx介导的hoxa 9a表达需要FGF信号传导。wnt 3a/wnt 8和cdx 1a/cdx 4两种形态突变体胚胎在中期分割时均不能促进体节的发生。这些数据表明cdx基因介导Wnt信号传导，并在斑马鱼后体的形态发生中发挥重要作用。(C)2004年爱思唯尔公司All rights reserved.
Although Wnt signaling plays an important role in body patterning during early vertebrate embryogenesis, the mechanisms by which Wnts control the individual processes of body patterning are largely unknown. In zebrafish, wnt3a and wnt8 are expressed in overlapping domains in the blastoderm margin and later in the tailbud. The combined inhibition of Wnt3a and Wnt8 by antisense morpholino oligonucleotides led to anteriorization of the neuroectoderm, expansion of the dorsal organizer, and loss of the posterior body structure-a more severe phenotype than with inhibition of each Wnt alone-indicating a redundant role for Wnt3a and Wnt8. The ventrally expressed homeobox genes vox, vent, and ved mediated Wnt3a/Wnt8 signaling to restrict the organizer domain. Of posterior body-formation genes, expression of the caudal-related cdx1a and cdx4/kugelig, but not bmps or cyclops, was strongly reduced in the wnt3a/wnt8 morphant embryos. Like the wnt3a/wnt8 morphant embryos, cdx1a/cdx4 morphant embryos displayed complete loss of the tail structure, suggesting that Cdx1a and Cdx4 mediate Wnt-dependent posterior body formation. We also found that cdx1a and cdx4 expression is dependent on Fgf signaling. hoxa9a and hoxb7a expression was down-regulated in the wnt3a/wnt8 and cdx1a/cdx4 morphant embryos, and in embryos with defects in Fgf signaling. Fgf signaling was required for Cdx-mediated hoxa9a expression. Both the wnt3a/wnt8 and cdx1a/cdx4 morphant embryos failed to promote somitogenesis during mid-segmentation. These data indicate that the cdx genes mediate Wnt signaling and play essential roles in the morphogenesis of the posterior body in zebrafish. (C) 2004 Elsevier Inc. All rights reserved.