Cloning and characterization of zebrafish smad2, smad3 and smad4
Cloning and characterization of zebrafish smad2, smad3 and smad4
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DOI：
10.1016/s0378-1119(00)00056-1
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发表时间：
2000-04-04
期刊：
影响因子：
3.5
通讯作者：
Hammerschmidt, M
中科院分区：
文献类型：
--
作者：
Dick, A;Mayr, T;Hammerschmidt, M
smad基因编码参与TGF β超家族成员信号转导的转录因子。本文报道了斑马鱼（Danio rerio）smad 2、smad 3和smad 4基因的克隆、鉴定和基因组定位。在非洲爪蟾中，smad 2过表达已被证明干扰原肠胚形成和背细胞命运特化。然而，全长斑马鱼smad 2，虽然在爪蟾外植体功能活跃，在斑马鱼胚胎中过表达时没有影响。相比之下，N-末端截短的，组成型活性版本的Smad 2蛋白导致严重的背侧化或部分第二轴的形成，指向Smad 2在中胚层和轴形成过程中的作用。利用发育RT-PCR和整体原位杂交技术研究了斑马鱼smad 2、3和4基因的时空表达模式。所有这三个基因都表现出强烈的和普遍存在的母性表达。合子的表达是弱的，普遍存在的情况下，smad 2，和强大的，普遍存在的情况下，smad 4，而smad 3显示了空间限制合子的表达模式。它表达在迁移神经嵴细胞的躯干和细胞的一个子集在间脑中的节点相关蛋白Cyclops/Ndr 2/Znr 1，一个潜在的信号上游Smad 2/3所需的眼场分离和底板规格的表达域非常接近。在剑水蚤突变胚胎中过表达截短的smad 2导致眼睛和底板缺陷的拯救。这些数据表明，Smad 2在斑马鱼中线信号传导过程中充当Nodal信号的介导者，而Smad 3可能参与了眼场分离的后续步骤。(C)2000 Elsevier Science B. V.保留所有权利。
smad genes encode transcription factors involved in the signal transduction of members of the TGF beta superfamily. We report here the cloning, characterization and genomic mapping of smad2, smad3 and smad4 from the zebrafish, Danio rerio. In Xenopus,, smad2 overexpression has been shown to interfere with gastrulation and dorsal cell fate specification. However, full-length zebrafish smad2, although functionally active in Xenopus explants, has no effect when overexpressed in zebrafish embryos. In contrast, an N-terminally truncated, constitutively active version of Smad2 protein causes severe dorsalization or partial secondary axis formation, pointing to a role of Smad2 during mesoderm and axis formation. The temporal and spatial expression patterns of zebrafish smad2, 3 and 4 were investigated by developmental RT-PCR and whole mount in-situ hybridization. All three genes show strong and ubiquitous maternal expression. Zygotic expression is weak and ubiquitous in the case of smad2, and strong and ubiquitious in the case of smad4, while smad3 shows a spatially restricted zygotic expression pattern. It is expressed in migrating neural crest cells of the trunk and a subset of cells in the diencephalon in close proximity to the expression domain of the Nodal-related protein Cyclops/Ndr2/Znr1, a potential signal upstream of Smad2/3 required for eye-field separation and floor plate specification. Overexpression of truncated smad2 in cyclops mutant embryos leads to a rescue of the eye and floorplate defects. These data suggest that Smad2 acts as a mediator of Nodal signals during zebrafish midline signaling, while Smad3 might be involved in later steps of eye field separation. (C) 2000 Elsevier Science B.V. All rights reserved.