Multiple Origins of Mesoderm in a Model Polychaete

模型多毛动物中中胚层的多重起源

• 批准号: 0544869
• 负责人: Elaine Seaver
• 金额: --
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0544869&HistoricalAwards=false
• 关键词: Multiple; Origins; Mesoderm; Model; Polychaete

Many animals generate their third germ layer, the mesoderm, from both endomesodermal and ectomesodermal sources during development. However, the cellular and molecular segregation of mesodermal developmental potential and the phylogenetic significance of these distinct origins remain unexplored. Embryos that display a highly stereotyped cell cleavage program called spiral cleavage (e. g. in animals that include mollusks, annelids, nemerteans, sipunculids, echiurans, polyclad flatworms) are ideal for tracing sources of larval/adult structures and have revealed both ectomesodermal and endomesodermal lineages. The proposed work combines molecular and cellular approaches with embryological manipulations in a polychaete model, Capitella sp. I, a segmented worm that undergoes spiral cleavage and adds new segments throughout its life history. Expression of engrailed, caudal, and eve in Capitella sp. I suggests that mesoderm in post-embryonic segments is not generated from endomesodermal teloblasts, but rather from ectomesodermal precursors that effectively 'gastrulate' throughout larval/juvenile life and give rise to adult segmental mesoderm during the process of terminal addition. In the proposed study, the mechanism by which mesodermal potential is generated from ectodermal and endodermal sources will be examined. An intracellular fate map for embryonic blastomeres of Capitella sp. I will be generated with special attention towards characterizing embryological origins of mesoderm. A number of mesodermal markers have been identified from Capitella sp. I, and will be mapped onto the cell lineage to determine which genes are associated with ectomesoderm, endomesoderm, or both. In an additional set of experiments, mis-expression and knockdown approaches will be utilized to determine the function of select ecto- and endomesodermal genes. The proposed study will integrate scientific training with research, and will include undergraduate, graduate, and postdoctoral trainees at the University of Hawaii, a minority institution and EPSCoR state. The PI is committed to training students in the laboratory environment, including those from underrepresented groups such as Pacific Islanders. The study will provide crucial information towards understanding how mesoderm is generated in polychaete annelids, and provide an important comparison of development of the third germ layer with ecdysosoan, deuterostome and other triploblastic animal systems.

许多动物在发育过程中从内中胚层和外中胚层来源产生第三胚层，即中胚层。然而，中胚层发育潜力的细胞和分子分离以及这些不同起源的系统发育意义仍有待探索。 具有高度定型细胞分裂程序（称为螺旋分裂）的胚胎（例如，在包括软体动物、环节动物、纽虫类、管虫类、鲎类、多包扁虫在内的动物中）是追踪幼虫/成虫结构来源的理想选择，并揭示了外中胚层和内中胚层谱系。拟议的工作将分子和细胞方法与多毛动物模型 Capitella sp 中的胚胎学操作结合起来。 I，一种分段蠕虫，在其整个生命史中经历螺旋分裂并添加新的分段。 engrailed、caudal 和 eve 在 Capitella sp 中的表达。我认为胚胎后节段中的中胚层不是由内中胚层端粒细胞产生的，而是由外中胚层前体产生的，这些前体在整个幼虫/幼虫生命中有效地“原肠胚形成”，并在最终添加过程中产生成虫节段中胚层。在拟议的研究中，将检查外胚层和内胚层来源产生中胚层潜力的机制。 Capitella sp 胚胎卵裂球的细胞内命运图。我将特别关注中胚层胚胎学起源的特征。已从 Capitella sp. 中鉴定出许多中胚层标记。 I，并将被映射到细胞谱系上以确定哪些基因与外中胚层、内中胚层或两者相关。在另一组实验中，将利用错误表达和敲低方法来确定选定的外胚层和内中胚层基因的功能。拟议的研究将把科学培训与研究结合起来，并将包括夏威夷大学、少数族裔机构和 EPSCoR 州的本科生、研究生和博士后学员。 PI 致力于在实验室环境中培训学生，包括来自太平洋岛民等代表性不足群体的学生。该研究将为了解多毛类环节动物中胚层如何产生提供重要信息，并提供第三胚层与蜕皮动物、后口动物和其他三叶动物系统发育的重要比较。