Barro O, Joly C, Condamine H, Boulekbache H
Laboratoire de Biologie du Développement, Université Paris 7, France.
Int J Dev Biol. 1994 Dec;38(4):613-22.
The widespread expression of the Xenopus homeobox gene Xhox3 in zebrafish was performed by microinjection of synthetic Xhox3 mRNA into uncleaved fertilized eggs and resulted in embryos displaying varying degrees of anterior-posterior (A-P) axis disruption. The phenotype observed was dose-dependent and showed anomalies, mainly in neural keel development, from microphthalmia to acephaly. Injection of 5 pg to 10 pg of mRNA caused a range of phenotypes in prim 5 stage embryos from normal to acephalic. Anomalies have been categorized according to an index of axis deficiency (Zf-IAD). We further characterized the axis disturbance by analyzing the expression of two genes implicated in axis formation: engrailed (eng) and brachyury (ntl). eng could not be detected in the muscle pioneer cells of embryos injected with Xhox3. The pattern distribution of brachyury (Ntl) protein is abnormal in Xhox3 injected embryos. Evidence for the conservation of the NH2 terminal region of the Xhox3 protein in frogs and fish is provided by the detection of a nuclear Xhox3-like protein in 24 h zebrafish embryos located in posterior mesoderm tissue. Previous results in Xenopus embryo research and the data presented here support the conservation of an A-P patterning mechanism involving the Xhox3 gene.
通过将合成的Xhox3 mRNA显微注射到未分裂的受精卵中，在斑马鱼中实现了非洲爪蟾同源框基因Xhox3的广泛表达，结果胚胎显示出不同程度的前后（A-P）轴破坏。观察到的表型呈剂量依赖性，主要在神经嵴发育方面表现出异常，从小眼畸形到无脑畸形。向原肠胚5期胚胎注射5 pg至10 pg的mRNA会导致从正常到无头的一系列表型。异常情况已根据轴缺陷指数（Zf-IAD）进行了分类。我们通过分析两个与轴形成相关的基因——engrailed（eng）和短尾（ntl）的表达，进一步对轴的干扰进行了表征。在注射了Xhox3的胚胎的肌肉先驱细胞中未检测到eng。在注射了Xhox3的胚胎中，短尾（Ntl）蛋白的模式分布异常。在24小时斑马鱼胚胎位于后中胚层组织中的核Xhox3样蛋白的检测，为青蛙和鱼类中Xhox3蛋白的NH2末端区域的保守性提供了证据。非洲爪蟾胚胎研究的先前结果以及此处呈现的数据支持了涉及Xhox3基因的A-P模式形成机制的保守性。
