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然未被探索。 胚胎显示出高度定型的细胞分裂程序，称为螺旋分裂（e。G.在包括软体动物、环节动物、纽形动物、星虫、echiurans、polyclad扁形虫在内的动物中）是追踪幼虫/成虫结构来源的理想方法，并揭示了外中胚层和内中胚层谱系。拟议的工作结合了分子和细胞的方法与胚胎学操作的多毛类动物模型，Capitella sp.我，一个分段蠕虫，经历螺旋分裂，并增加了新的部分在其整个生命史。我表明，中胚层在胚后段不产生endomesodermal端细胞，而是从外胚层中胚层前体，有效地'原肠胚'在整个幼虫/少年的生活，并引起成人节段中胚层在终端添加的过程中。在拟定的研究中，将检查外胚层和内胚层来源产生中胚层潜能的机制。一个细胞内的命运地图的胚胎卵裂球的Capitella的。我将产生特别注意对胚胎起源的中胚层的特点。已经从Capitella sp. I中鉴定出许多中胚层标记物，并将其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。在另外一组实验中，将利用错误表达和敲低方法来确定选择的外胚层和内中胚层基因的功能。这项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的本科生、研究生和博士后学员，夏威夷大学是一所少数民族院校，也是EPSCoR州。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的群体的学生。这项研究将为了解多毛类环节动物中胚层是如何产生的提供重要信息，并提供与蜕皮动物，后口动物和其他三胚层动物系统的第三胚层发育的重要比较。