...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Development >Tripartite organization of the ancestral chordate brain and the antiquity of placodes: insights from ascidian Pax-2/5/8, Hox and Otx genes.
【24h】

Tripartite organization of the ancestral chordate brain and the antiquity of placodes: insights from ascidian Pax-2/5/8, Hox and Otx genes.

机译：祖先的brain脉大脑的三方组织和上古的斑块：来自海生Pax-2 / 5/8，Hox和Otx基因的见解。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Ascidians and vertebrates belong to the Phylum Chordata and both have dorsal tubular central nervous systems. The structure of the ascidian neural tube is extremely simple, containing less than 400 cells, among which less than 100 cells are neurons. Recent studies suggest that, despite its simple organization, the mechanisms patterning the ascidian neural tube are similar to those of the more complex vertebrate brain. Identification of homologous regions between vertebrate and ascidian nervous systems, however, remains to be resolved. Here we report the expression of HrPax-258 gene: an ascidian homologue of vertebrate Pax-2, Pax-5 and Pax-8 genes. Molecular phylogenetic analyses indicate that HrPax-258 is descendant from a single precursor gene that gave rise to the three vertebrate genes. The expression pattern of HrPax-258 suggests that this subfamily of Pax genes has conserved roles in regional specification of the brain. Comparison with expression of ascidian Otx (Hroth) and a Hox gene (HrHox1) by double-staining in situ hybridizations indicate that the ascidian brain region can be subdivided into three regions; the anterior region marked by Hroth probably homologous to the vertebrate forebrain and midbrain, the middle region marked by HrPax-258 probably homologous to the vertebrate anterior hindbrain (and maybe also midbrain) and the posterior region marked by Hox genes which is homologous to the vertebrate hindbrain and spinal cord. Later expression of HrPax-258 in atrial primordia implies that basal chordates such as ascidians have already acquired a sensory organ that develops from epidermal thickenings (placodes) and expresses HrPax-258; we suggest it is homologous to the vertebrate ear. Therefore, placodes are not likely to be a newly acquired feature in vertebrates, but may have already been possessed by the earliest chordates.
机译：海生动物和脊椎动物都属于Phylum Chordata，都具有背管中枢神经系统。海鞘神经管的结构极其简单，包含少于400个细胞，其中神经元少于100个细胞。近期研究表明，尽管其组织简单，但形成海马神经管的机制却与更复杂的脊椎动物脑相似。然而，脊椎动物和海鞘神经系统之间同源区域的鉴定尚待解决。在这里，我们报告HrPax-258基因的表达：脊椎动物Pax-2，Pax-5和Pax-8基因的海鞘同源物。分子系统发育分析表明，HrPax-258是来自单个前体基因的后代，后者产生了三个脊椎动物基因。 HrPax-258的表达模式表明，该Pax基因亚家族在大脑的区域特征中具有保守的作用。通过双重染色原位杂交与海藻Otx（Hroth）和Hox基因（HrHox1）的表达比较表明，海鞘脑区域可分为三个区域。 Hroth标记的前区可能与脊椎动物前脑和中脑同源，HrPax-258标记的中区可能与脊椎动物前后脑（也可能是中脑）同源，Hox基因标记的后区与脊椎动物同源后脑和脊髓。 HrPax-258在心房原基中的后期表达意味着诸如海胆类的基础脊索已经获得了一种感觉器官，该感觉器官是由表皮增厚形成的并表达HrPax-258。我们建议它与脊椎动物的耳朵同源。因此，斑纹在脊椎动物中不太可能成为新近获得的特征，但最早的脊索动物可能已经拥有它们。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号