Cytokinesis and RNA Segregation in Zebrafish Development

描述（由申请人提供）：细胞分裂是子细胞分裂的物理过程，对发育和生长调节至关重要。在许多情况下，细胞质分裂与细胞决定因子的不对称分离相结合，这反过来导致细胞类型的功能多样化。生物学中的一个基本问题是了解细胞命运决定因素分离的分子机制，特别是胚质，一种赋予生殖细胞命运的特殊细胞质。对斑马鱼（Danio rerio）母体效应突变的系统筛选已经确定了影响细胞质分裂和种质分离过程的基因，这些基因在这种生物体中是密切相关的。据我们所知，这是第一次在脊椎动物基因中发现细胞分裂所需的突变。这一建议的重点是分析这些基因之一的功能，细胞岛，我们显示编码极光B激酶，一种参与沟起始的染色体乘客蛋白。该基因的功能分析表明，它在胚胎胚盘外侧而非内侧区域的沟形成中起重要作用。我们将测试来自不同微管结构的诱导沟信号的假设，可能通过不同的下游介质（如Aurora B激酶）的作用，是胚盘不同区域的细胞分裂所必需的。该研究还将确定这些信号在种质招募形成沟过程中的确切作用。对这些机制的理解将有助于了解早期脊椎动物胚胎的基本细胞过程（细胞质分裂）和基本发育过程（种质分离），以及它们之间的功能关系。

DESCRIPTION (provided by applicant): Cytokinesis, the physical process that divides daughter cells, is of critical importance to development and growth regulation. In many instances, cytokinesis is coupled with the asymmetric segregation of cellular determinants, which in turn results in the functional diversification of cell types. A basic question in biology is to understand the molecular mechanisms underlying the segregation of cell fate determinants, in particular the germ plasm, a specialized cytoplasm that confers the germ cell fate. Systematic screens for maternal-effect mutations in the zebrafish, Danio rerio, have identified genes that affect the processes of cytokinesis and germ plasm segregation, which in this organism are intimately linked. To our knowledge, these are the first identified mutations in vertebrate genes required for cytokinesis. This proposal focuses on the analysis of the function of one of these genes, Cellular Island, which we show codes for Aurora B kinase, a chromosomal passenger protein involved in furrow initiation. Functional analysis of this gene suggests that it has an essential role in furrow formation in lateral, but not medial, regions of the embryonic blastodisc. We will test the hypothesis that furrow-inducing signals from different microtubule-based structures, possibly through the action of distinct downstream mediators such as Aurora B kinase, are required for cytokinesis in separate regions of the blastodisc. The proposed research will also determine the precise roles of these signals in the process of germ plasm recruitment to the forming furrow. The understanding of these mechanisms will provide insights on both a fundamental cellular process (cytokinesis) and a fundamental developmental process (germ plasm segregation), and the functional relationship between them in the early vertebrate embryo. The proposed research addresses fundamental mechanisms of cell division and the determination of cell fate, in particular, the specification of the germ cells. Knowledge acquired through these studies will lead to progress in therapies that alleviate health problems related to reproductive biology, cancer, and stem cell and tissue development.