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Egg Cytoplasmic Factors that Regulate Developmental Pattern

调节发育模式的卵细胞质因子

基本信息

批准号：
04044089
负责人：
SATOH Noriyuki
金额：
$ 3.78万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04044089/
关键词：
Developmental pattern Egg cytoplasmic factors gene expression Notochord Muscle Pigment cells Prochordates Evolution

项目摘要

A recent molecular-phylogenetic study based on the comparison of 18S rDNA sequences has suggested that formation of tadpole larvae is a key developmental event to understand the origin and evolution of chordates. During embryogenesis of ascidians, about forty unicellular and striated muscle cells as well as forty notochord cells are formed in the tail of the larva. Therefore, it is important to study molecular mechanisms involved in differentiation of these cells to understand not only ontogeny by also phylogeny of animals.We have isolated an ascidian homolog of the mouse T (Brachyury) gene. The ascidian T gene is expressed exclusively in notochord cells and the expression begins with the time of restriction of their developmental fates. Therefore, the T gene is cue to understand the chordate evolution. We are now studying the T gene expression in ascidians which develop tailless larvae.Muscle cell differentiation in ascidian embryos has been studied at the levels of muscle actin genes, myogenic regulatory gene, and cytoplasmic factors (or muscle determinants). We have also studied muscle actin genes in ascidians with tailless larvae, and it was found that the ascidian with tailless larvae contains several pseudogenes of muscle actin, which were not found in ascidians with tailed larvae under usual research conditions we adopted.

最近一项基于 18S rDNA 序列比较的分子系统发育研究表明，蝌蚪幼虫的形成是了解脊索动物起源和进化的关键发育事件。在海鞘的胚胎发生过程中，幼虫尾部形成约四十个单细胞和横纹肌细胞以及四十个脊索细胞。因此，研究参与这些细胞分化的分子机制对于了解动物的个体发育和系统发育非常重要。我们分离出了小鼠 T (Brachyury) 基因的海鞘同源物。海鞘T基因仅在脊索细胞中表达，并且在其发育命运受到限制时开始表达。因此，T基因是了解脊索动物进化的线索。我们现在正在研究发育无尾幼虫的海鞘中T基因的表达。已经在肌肉肌动蛋白基因、肌源性调节基因和细胞质因子（或肌肉决定因素）水平上研究了海鞘胚胎中的肌肉细胞分化。我们还对无尾幼体海鞘的肌肉肌动蛋白基因进行了研究，发现无尾幼体海鞘中含有多个肌肉肌动蛋白假基因，而在我们采用的通常研究条件下，无尾幼体海鞘中没有发现这些肌肉肌动蛋白假基因。