Cell Lineage in the Developmental Biology of Sea Urchins

海胆早期发育的分子机制 必须用胚胎细胞谱系来解释。的 本研究的目的是进一步探讨 海胆发育中的细胞谱系关系 胚胎和幼虫。采取了多种方法：1）建立在 现有的，部分完成的数据库，一些研究将 解决S系中未解决的问题。紫色的 胚胎通过进一步定义血统和规格内 最终的植物板块，通过更完整地确定 八个小微粒的命运，并通过描述起源 2）描述调节性神经母细胞的谱系变化; 发展，一组实验将比较正常的血统 在孤立的动物帽细胞谱系的模式 用LiCl处理或与微粒融合，并将比较 正常的谱系模式与四分之一胚胎的谱系模式相同， 及3）提供世系及规格的描述， 幼棘皮动物的形态发生， 组织特异性标记基因在S.紫色的 将通过原位杂交研究幼虫。 %%% 发育生物学的一个基本问题是， 在成体中发现的细胞类型来自于单个受精卵， 蛋这项研究将追踪创始细胞的细胞命运， 受精后的极早期分裂形成最终形态 在一个幼虫。它还将探讨决定 这些细胞的命运

The molecular mechanisms of early development in the sea urchin must be interpreted in terms of the embryonic cell lineage. The purpose of this investigation is to further explore the role of cell lineage relationships in the development of sea urchin embryos and larvae. A multiple approach is taken: 1) Building on the existing, partially completed database, some studies will address unsolved problems in the lineage of the S. purpuratus embryo by further defining the lineage and specification within the definitive vegetal plate, by determining more completely the fate of the eight small micromeres, and by describing the origins of the neuroblasts; 2) To describe lineage changes in regulative development, a group of experiments will compare normal lineage patterns with the lineage of cells in isolated animal caps treated with LiCl or fused with micromeres and will compare normal lineage patterns with those of meridional quarter embryos, and 3) To provide descriptions of lineage and specification in the morphogenesis of the juvenile echinoderm, the expression of histospecific marker genes in the rudiment of S. purpuratus larvae will be investigated by in situ hybridization. %%% A fundamental problem in developmental biology is how the various cell types found in an adult are derived from a single fertilized egg. This study will trace the cell fates of founder cells from very early divisions after fertilization to their ultimate form in a larvae. It will also explore the factors which determine the fate of those cells.