Mechanisms of Intracellular Scaling

细胞内缩放的机制

• 批准号: 8516062
• 负责人: Rebecca W Heald
• 金额: $ 43.01万
• 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/8516062
• 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（由申请人提供）：研究细胞内缩放细胞大小的机制在不同的生物体以及在不同组织类型的同一生物体中以及在发育过程中，对细胞器和内部结构提出可变的代谢和功能需求。一个基本问题是，基本的亚细胞成分（例如细胞核，有丝分裂纺锤体和染色体）如何受到调节以适应细胞尺寸的差异。 Xenopus蛙提供了两个生理环境，我们可以在其中研究这个问题。首先，我们可以将爪诺乱的laevis与较小的相关物种的热带物质进行比较，该物种产卵较小，并且在整个发育过程中具有成比例的较小细胞。其次，我们可以比较爪蟾laevis胚胎发生的不同阶段，因为〜1毫米直径卵快速裂解以形成较小的胚泡，该胚胎由第15个分裂降低至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物，这些卵和胚胎会在体外概括细胞器缩放，我们可以用来鉴定大小变化的分子差异。我们的第一个特定目的集中在有丝分裂主轴上，我们利用计算机模拟来识别微管动力学和组织的参数，这些参数可能有助于物种和开发过程中的纺锤体大小和形态变化。该目标还开发了新的方法来检查外部缩放机制，通过物理上限制不同大小液滴内的主轴组件反应，这将揭示是否存在尺寸阈值来缩放外部主轴或更改组件途径。 AIM 2研究了在发育过程中如何改变有丝分裂染色体的大小，以与纺锤长度进行协调，从而完全隔离。在AIM 3中，我们开始通过检查Xenopus laevis发育过程中改变核大小的后果来解决细胞器缩放的重要性。这些实验将提供有关缩放量表的发生方式并有助于细胞内形态发生和细胞分裂的洞察力，对生存力和发育必不可少的过程以及包括癌症在内的人类疾病中的缺陷。