The Evolution of Embryonic Polarity: A Molecular and Phylogenetic Approach

AbstractThis补助金的重点是了解发育和进化起源的胚胎轴属性，负责组织的分离，在一个小的孤立的海葵Nematostella vectensis（珊瑚虫，刺胞动物）的胚层。 珊瑚虫是双胚层、“放射状”对称的刺胞动物门的基础成员：是所有两侧对称的三胚层后生动物的姐妹门。 与两侧对称的后生动物不同，N. vectensis卵没有明显的分子极性，在受精时或受精后不久产生的不对称性导致在原肠胚形成的未来位点激活核β-连环蛋白信号。 因为刺胞动物如N. vectensis具有许多与两侧性动物中的轴向组织相关的基因，它们有可能为揭示所有多细胞动物中导致卵各向异性进化的机制提供线索。（2）研究PAR蛋白在建立微孢子虫卵/合子早期不对称性中的作用。vectensis受精卵，并确定这些蛋白质在调节不对称β-连环蛋白信号传导中的可能作用。这些实验将确定刺胞动物中par基因的功能，并将揭示刺胞动物是否像双侧刺胞动物那样使用这些基因来发育早期卵/胚胎。此外，这些实验将揭示PAR蛋白是否在极化经典Wnt信号传导中起功能作用。3）产生关键试剂并进一步开发进一步开发N. vectensis作为发育和进化研究的模式系统。这项工作是第一个全面的实验和分子分析的珊瑚虫刺胞体发育。 它提供了一个独特的机会来了解这些胚胎是如何“工作”的，从而为更普遍研究的双侧系统的发展提供了见解。这些研究将精子来源的不对称性与PAR蛋白的定位和Wnt/β-catenin信号转导通路的激活联系起来，从而为A/V轴的进化和胚层的进化提供了见解。拟议的工作涉及博士后，研究生和本科生，他们来自科学领域代表性不足的群体。这项研究的结果也将纳入本科和研究生课程。此外，拟议的合作工作还将改善夏威夷大学的研究和培训基础设施。

AbstractThis grant is focused on understanding the developmental and evolutionary origin of embryonic axial properties that are responsible for organizing the segregation of germ layers in a small solitary sea anemone Nematostella vectensis (Anthozoa, Cnidaria). Anthozoans are basal members of the diploblastic, "radially" symmetric Cnidaria: the sister phylum to all bilaterally symmetrical triploblastic metazoans. Unlike bilaterally symmetrical metazoans, N. vectensis eggs have no apparent molecular polarity, and asymmetries generated at, or soon after, fertilization result in the activation of nuclear beta-catenin signaling at the future site of gastrulation. Because cnidarians like N. vectensis possess many of the same genes involved in axial organization in bilaterians, they have the potential to provide insight into the mechanisms that led to the evolution of egg anisotropies in all multicellular animals.Three specific aims will be pursued: 1) To use experimental embryological methods to characterize the onset of axis formation and origins of developmental polarity in the N. vectensis egg/zygote, 2) To identify the roles of the PAR proteins in establishing early asymmetries in the N. vectensis zygote and determine the possible role of these proteins in regulating asymmetric beta-catenin signaling. These experiments will establish the function of the par genes in a cnidarian and will reveal if cnidarians use these genes to polarize the early egg/embryo as in bilaterians. Additionally, these experiments will reveal if the PAR proteins play a functional role in polarizing canonical Wnt signaling, 3) To produce the critical regents and further develop methodologies necessary for further exploitation of N. vectensis as a model system for developmental and evolutionary studies.This work is the first comprehensive experimental and molecular analysis of anthozoan cnidarian development. It provides a unique opportunity to understand how these embryos "work", and thus provide insight into the development of more commonly studied bilaterian systems. These studies will link sperm-derived asymmetries to the localization of the PAR proteins and the activation of the Wnt/beta-catenin signal transduction pathway, and thus, provide insight into the evolution of the A/V axis and the evolution of germ layers. The proposed work involves postdocs, graduate students and undergraduate students from groups under-represented in science. The findings from this research will also incorporated into the undergraduate and graduate curricula. Additionally, the proposed collaborative work will also improve the research and training infrastructure at the University of Hawaii.