Mechanisms of Intracellular Scaling

细胞内缩放的机制

• 批准号: 8704954
• 负责人: Rebecca W Heald
• 金额: $ 44.57万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8704954
• 关键词: Address; Affect; Animals; Area; Biology; Caliber; Cell Division Process; Cell Nucleus; Cell Size; Cell division; Cells; Cellular biology; Centrosome; Chromatin; Chromosomes; Cleaved cell; Computer Simulation; Data; Defect; Development; Embryo; Embryonic Development; Encapsulated; Evolution; Genome; Histocompatibility Testing; Importins; In Situ; In Vitro; Kinesin; Lead; Length; Light; Malignant Neoplasms; Mediating; Meiosis; Metabolic; Methods; Microfluidics; Microtubule Stabilization; Microtubule-Associated Proteins; Microtubules; Mitotic Chromosome; Mitotic spindle; Molecular; Monomeric GTP-Binding Proteins; Morphogenesis; Morphology; Nuclear; Nuclear Import; Organelles; Organism; Pathway interactions; Phase; Phosphorylation; Physiological; Process; Rana; Reaction; Regulation; Regulation of Cell Size; Research; Role; Running; Site; Staging; Structure; Subcellular structure; System; Techniques; Testing; Titrations; Work; Xenopus; Xenopus laevis; blastocyst; cell type; daughter cell; egg; embryo stage 2; human disease; in vivo; insight; katanin; millimeter; novel; nucleocytoplasmic transport; pointed protein; receptor; research study; segregation; simulation

DESCRIPTION (provided by applicant): Investigating Mechanisms of Intracellular Scaling Cell size varies widely among different organisms as well as within the same organism in different tissue types and during development, placing variable metabolic and functional demands on organelles and internal structures. A fundamental question is how essential subcellular components such as the nucleus, mitotic spindle and chromosomes are regulated to accommodate cell size differences. Xenopus frogs offer two physiological contexts in which we can investigate this question. First, we can compare Xenopus laevis to the smaller, related species Xenopus tropicalis, which lays smaller eggs and has proportionally smaller cells throughout development. Second, we can compare different stages of Xenopus laevis embryogenesis, as the ~1 millimeter diameter egg rapidly cleaves to form smaller blastomeres, which by the 15th division are reduced to 40 microns across. A unique aspect of our approach is to prepare cytoplasmic extracts from eggs and embryos that recapitulate organelle scaling in vitro, which we can use to identify molecular differences that underlie size changes. Our first specific aim focuses on the mitotic spindle, and we take advantage of computer simulations to identify parameters of microtubule dynamics and organization that could contribute to spindle size and morphology changes between species and during development. This aim also develops novel methods to examine extrinsic scaling mechanisms by physically confining spindle assembly reactions inside different sized droplets, which will reveal whether there are size thresholds that scale the spindle externally or alter assembly pathways. Aim 2 investigates how the size of mitotic chromosomes is altered during development to coordinate with spindle length so that complete segregation occurs. In Aim 3, we begin addressing the importance of organelle scaling by examining the consequences of altering nuclear size during development in Xenopus laevis. These experiments will provide insight into how scaling occurs and contributes to intracellular morphogenesis and cell division, processes essential for viability and development, and defective in human diseases including cancer.

描述(申请人提供)：研究细胞内伸缩的机制细胞大小在不同生物体以及同一生物体内不同组织类型和发育过程中差异很大，对细胞器和内部结构提出不同的代谢和功能需求。一个基本的问题是，如何调节基本的亚细胞成分，如核、有丝分裂纺锤体和染色体，以适应细胞大小的差异。非洲爪蛙提供了两种生理环境，我们可以在其中研究这个问题。首先，我们可以将非洲爪哇与体型较小的近缘物种非洲爪哇进行比较，热带非洲爪哇产卵较小，在整个发育过程中细胞比例较小。其次，我们可以比较非洲爪哇胚胎发育的不同阶段，直径约1毫米的卵子迅速分裂形成更小的卵裂球，到第15次分裂时，卵裂球的直径减少到40微米。我们方法的一个独特方面是从卵子和胚胎中制备细胞质提取液，这些提取液可以概括细胞器在体外的缩放情况，我们可以使用这些提取液来识别导致大小变化的分子差异。我们的第一个具体目标是有丝分裂纺锤体，我们利用计算机模拟来确定微管动力学和组织参数，这些参数可能有助于纺锤体大小和形态在物种之间和发育过程中的变化。这一目标还开发了通过物理限制不同大小液滴内的主轴组装反应来研究外部缩放机制的新方法，这将揭示是否存在从外部缩放主轴或改变组装路径的尺寸阈值。目的2研究有丝分裂染色体的大小在发育过程中如何改变以与纺锤体长度相协调，从而实现完全分离。在目标3中，我们通过研究非洲爪哇在发育过程中改变核大小的后果，开始讨论细胞器缩放的重要性。这些实验将深入了解结垢是如何发生的，并有助于细胞内的形态发生和细胞分裂，对生存和发育至关重要的过程，以及包括癌症在内的人类疾病的缺陷。