Ectopic expression and knockdown of a zebrafish sox21 reveal its role as a transcriptional repressor in early development
Ectopic expression and knockdown of a zebrafish sox21 reveal its role as a transcriptional repressor in early development
复制标题
DOI：
10.1016/j.mod.2004.01.001
复制
发表时间：
2004-02-01
影响因子：
2.6
通讯作者：
Beltrame, M
中科院分区：
文献类型：
--
作者：
Argenton, F;Giudici, S;Beltrame, M
Sox蛋白是属于HMG box超家族的DNA结合蛋白，在动物胚胎发育中起着关键作用。斑马鱼Sox 21 a是B组Sox蛋白的一部分，其鸡和小鼠直系同源物已被描述为在两种不同的靶基因背景下分别作为转录抑制子和激活子。斑马鱼sox 21 a基因在卵母细胞中以母体转录本的形式存在，主要表达于神经胚形成开始时发育中的中脑-后脑边界。为了了解其在体内的作用，我们通过显微注射异位表达sox 21 a。全长sox 21 a的异位表达导致胚胎背侧化。背化胚胎的一个子集显示部分轴分裂，因此异位神经管，作为一个额外的表型。在原肠胚形成时，注射的胚胎显示出组织特异性基因（如脊索蛋白和类鹅蛋白）的表达域的扩展。在体节发生中使用的分子标记突出显示，sox 21 a注射的胚胎具有缩短的AP轴，起伏的轴结构，扩大甚至放射状的近轴区域。由sox 21 a异位表达引起的发育异常提示会聚-伸展形态发生运动的缺陷。反义吗啉代寡核苷酸，设计为功能性敲低sox 21 a，导致胚胎腹侧化。此外，获得功能的嵌合构建体，其中Sox 21 a DNA结合结构域融合到转录激活因子（VP 16）或阻遏物（EnR）域的实验表明，斑马鱼Sox 21 a作为一个阻遏物在背腹图案。(C)2003爱思唯尔爱尔兰有限公司保留所有权利。
Sox proteins are DNA-binding proteins belonging to the HMG box superfamily and they play key roles in animal embryonic development. Zebrafish Sox21a is part of group B Sox proteins and its chicken and mouse orthologs have been described as transcriptional repressor and activator, respectively, in two different target gene contexts. Zebrafish sox21a is present as a maternal transcript in the oocyte and is mainly expressed at the developing midbrain-hindbrain boundary from the onset of neurulation. In order to understand its role in vivo, we ectopically expressed sox21a by microinjection. Ectopic expression of full length sox21a leads to dorsalization of the embryos. A subset of the dorsalized embryos shows a partial axis splitting, and hence an ectopic neural tube, as an additional phenotype. At gastrulation, injected embryos show expansion of the expression domains of organizer-specific genes, such as chordin and goosecoid. Molecular markers used in somitogenesis highlight that sox21a-injected embryos have shortened AP axis, undulating axial structures, enlarged or even radialized paraxial territory. The developmental abnormalities caused by ectopic expression of sox21a are suggestive of defects in convergence-extension morphogenetic movements. Antisense morpholino oligonucleotides, designed to functionally knockdown sox21a, cause ventralization of the embryos. Moreover, gain-of-function experiments with chimeric constructs, where Sox21a DNA-binding domain is fused to a transcriptional activator (VP16) or repressor (EnR) domain, suggests that zebrafish Sox21a acts as a repressor in dorso-ventral patterning. (C) 2003 Elsevier Ireland Ltd. All rights reserved.