Cytokinesis and RNA segregation in zebrafish development

斑马鱼发育中的细胞分裂和RNA分离

• 批准号: 7021388
• 负责人: FRANCISCO J PELEGRI
• 金额: $ 23.9万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2007-05-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7021388
• 关键词: actins; alleles; cell adhesion; cell growth regulation; cell type; chromosome movement; cytokine; cytoskeleton; developmental genetics; embryo /fetus cell /tissue; embryogenesis; exocytosis; gene mutation; genetic markers; germ cells; intracellular transport; linkage mapping; messenger RNA; microfilaments; microtubules; mutant; oogenesis; phenotype; physical process; zebrafish

Cytokinesis, the physical process that divides daughter cells, is of fundamental 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. During the systematic identification of maternal-effect mutations in the zebrafish, two mutations, in the genes aura and nebel, were identified which affect both of these processes. Mutations in these genes result in embryonic lethality due to defects in cell adhesion and membrane deposition. In both cases, the basis of this phenotype is a defect in the completion of cytokinesis, possibly in the addition or stabilization of new membrane at the cleavage plane. In addition, both of these mutations affect different steps in a pathway of segregation of the vasa RNA, a component of a specialized cytoplasm that confers the germ cell fate. Both types of defects may be based on the inability of the cytoskeleton to undergo specific rearrangements required for its function: aura-dependent microfilament rearrangements at multiple stages during early cleavage and nebel-dependent microtubule reorganization at the forming furrow. The proposed research will determine the precise roles of these genes in the process of cytokinesis and the segregation of the vasa RNA. For this purpose we will use cell biological techniques to visualize cellular components in wild-type and mutant embryos and inhibitor studies to determine the role of subcellular processes or networks. In addition, we will determine the molecular identity of the affected genes through a positional cloning approach. The understanding of these processes will provide insights on a variety of poorly understood subjects: i) the processes involved in the completion of cytokinesis, ii) the asymmetric segregation of RNA and other products within dividing cells, and iii) the functional relationship between the cellular mechanisms required for these two processes.

胞质分裂是分裂子代细胞的物理过程，对发育和生长调节至关重要。在许多情况下，胞质分裂与细胞决定因素的不对称分离相结合，这反过来又导致细胞类型的功能多样化。在对斑马鱼母体效应突变进行系统鉴定的过程中，在基因AURA和Nebel中发现了两个影响这两个过程的突变。由于细胞黏附和膜沉积的缺陷，这些基因的突变会导致胚胎死亡。在这两种情况下，这种表型的基础是细胞质分裂完成的缺陷，可能是在卵裂面增加或稳定新的膜。此外，这两个突变都影响到Vasa RNA分离途径的不同步骤，Vasa RNA是一种特殊细胞质的成分，决定了生殖细胞的命运。这两种类型的缺陷都可能基于细胞骨架不能进行其功能所需的特定重排：在早期卵裂的多个阶段依赖于光环的微丝重排，以及在形成沟槽时依赖于Nebel的微管重组。这项拟议的研究将确定这些基因在胞质分裂和VasA RNA分离过程中的确切作用。为此，我们将使用细胞生物学技术可视化野生型和突变胚胎中的细胞成分，并进行抑制研究，以确定亚细胞过程或网络的作用。此外，我们将通过定位克隆的方法来确定受影响基因的分子同一性。对这些过程的理解将提供对许多鲜为人知的主题的见解：i)完成胞质分裂所涉及的过程，ii)RNA和其他产物在分裂细胞中的不对称分离，以及iii)这两个过程所需的细胞机制之间的功能关系。