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Segmentation in Vertebrates

脊椎动物的分割

基本信息

批准号：
10680688
负责人：
TAKAHASHI Yoshiko
金额：
$ 1.92万
依托单位：
NARA INSTITUTE OF SCIENCE AND TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

项目摘要

During early development in vertebrates, the mesoderm plays a central role in specification and: establishment of the body patterning. We aimed at understanding the mechanisms by which the mesoderm specification is regulated by mainly focusing on three major topics : 1) Subdivision of the mesoderm along the dorso-ventral: axis of the body, 2) Binary decision of the lateral plate, 3) Somite segmentation along the antero-posterior axis of the body.1) The mesoderm is subdivided into the dorsal (somite) and ventral (lateral plate) regions, We found that different concentrations of BMP4, a signalling molecule belonging to TGFb family, determine these distinct mesodermal types.2) The lateral plate mesoderm is subdivided into two distinct layers, somatopleure and splanchnopleure., The former one contributes to the outer body underlying the skin and the latter one to the inner mesoderm surrounding the"gut organ. We found that the somatopleure is specified by its overlying; ectoderm whereas the splanchnopleure is influenced by the adjacent endoderm.3) Most of the antero-posteriorly reiterated structures such as back bones and ribs are attributed to the somite segmentation at earlier stages in development. A pair of somites pinches off from the unsegmented somite successively along the antero-posterior axis, thus the segmentation proceeds from head to tail. We found that at the next segmentation site a microinductive event between the adjacent cells takes place leading, to a morphological boundary. Particularly, the posteriorly positioned cells to the boundary play primary roles in instructing their anterior cells to make a boundary. We designated this activity as a "segmenter".Our novel knowledge concerning the mesodermal subdivision will open a way to understand how a simple structure gives rise to more complex organization during early development.

在脊椎动物的早期发育过程中，中胚层在规格和身体模式的建立中发挥着核心作用。我们旨在了解中胚层规范的调节机制，主要关注三个主要主题：1）中胚层沿背腹侧：身体轴的细分，2）侧板的二元决策，3）沿身体前后轴的体节分割。1）中胚层细分为背侧（体节）和腹侧（侧板）区域，我们发现不同浓度的 BMP4（属于 TGFb 家族的信号分子）决定了这些不同的中胚层类型。2）侧板中胚层细分为两个不同的层，体层和内脏层。前一层贡献于皮肤下方的外部身体，后者贡献于“肠道器官”周围的内部中胚层。我们发现 somatopleure 由其覆盖层指定；外胚层，而内胚层则受到邻近内胚层的影响。3) 大多数前后重复的结构，如背骨和肋骨，都归因于发育早期阶段的体节分割。一对体节沿着前后轴依次从未分节的体节中掐断，从而分节从头到尾进行。我们发现，在下一个分割位点，相邻细胞之间发生微感应事件，导致形态边界。特别是，位于边界后面的细胞在指示其前面的细胞形成边界方面起着主要作用。我们将这项活动命名为“分割器”。我们关于中胚层细分的新知识将为理解简单的结构如何在早期产生更复杂的组织开辟一条道路。发展。