MAPK Function in the Ilyanassa Organizer

Ilyanassa Organizer 中的 MAPK 功能

• 批准号: 0091392
• 负责人: Lisa Nagy
• 金额: $ 36万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0091392&HistoricalAwards=false
• 关键词: MAPK; Function; Ilyanassa; Organizer

0091392NagyThe mud snail Ilyanassa obsoleta has long been a model for the study of developmental mechanisms because it provides a spectacular example of localization of cytoplasmic determinants. Ilyanassa has a distinctive pattern of cell division known as spiral cleavage, which it shares with several other phyla. In addition, it extrudes a cytoplasmic bulb - the polar lobe- during its first two cleavages. When the polar lobe is removed, the embryo lacks a dorsal-ventral axis and has a radial symmetry. Not only are the direct physical descendants of the polar lobe - the D quadrant cells - missing in polar lobe ablated embryos, but lobeless embryos lack structures known to descend from other quadrants. Thus, through a process of cytoplasmic localization, the polar lobe provides one or more cells in the D quadrant with the ability to induce the fates of non-D cells. The localization of polar lobe determinants thus specifies the D quadrant as the organizer of the Ilyanassa dorsal-ventral axis. Although it has been nearly 100 years since the discovery of the effects of the polar lobe, (Crampton, 1896) the molecular mechanisms underlying the localization of the organizing activity to the D quadrant, as well as the nature of the organizing activity itself, remain unknown. Dr. Nagy and her lab have identified the first known component of the molluscan organizer: a localized activation of mitogen-activated protein kinase (MAPK) that spreads from the 3D macromere to all cells that require the D quadrant signal for normal development. Based on their results, they propose that the activation of MAPK in 3D results from inheriting polar lobe determinants, and that MAPK is a component of a signaling pathway that transduces the inductive signal from 3D to specify cell fate in other lineages. The aims of this grant are to probe the mechanisms by which MAPK is activated in the 3D macromere, the mechanisms by which the D quadrant signals to the rest of the embryo and the mechanism by which MAPK specifies cell fates in other lineages.

[01:13 . 92]泥蜗牛Ilyanassa obsoleta长期以来一直是研究发育机制的一个模型，因为它提供了细胞质决定因素定位的一个壮观的例子。Ilyanassa有一种独特的细胞分裂模式，称为螺旋切割，它与其他几个门相同。此外，它在前两次分裂中挤出一个细胞质球——极叶。当极叶切除后，胚胎缺少背腹轴，呈径向对称。在极叶消融的胚胎中，不仅极叶的直接物理后代——D象限细胞——缺失，而且无叶胚胎缺乏已知来自其他象限的结构。因此，通过细胞质定位过程，极叶为D象限的一个或多个细胞提供了诱导非D细胞命运的能力。因此，极叶决定因素的定位将D象限指定为Ilyanassa背腹轴的组织者。尽管自发现极叶效应以来已经将近100年了，（Crampton, 1896）组织活动定位于D象限的分子机制，以及组织活动本身的性质，仍然未知。Nagy博士和她的实验室已经确定了软体动物组织者的第一个已知成分：有丝分裂原激活蛋白激酶（MAPK）的局部激活，从3D大细胞扩散到所有需要D象限信号才能正常发育的细胞。基于他们的研究结果，他们提出MAPK在3D中的激活是由于继承了极叶决定因子，并且MAPK是信号通路的一个组成部分，该信号通路将来自3D的感应信号转导到其他谱系中指定细胞命运。这项资助的目的是探索MAPK在3D大细胞中被激活的机制，D象限向胚胎其余部分发出信号的机制，以及MAPK在其他谱系中指定细胞命运的机制。