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Mechanisms of Intracellular Scaling

细胞内缩放的机制

基本信息

批准号：
8906883
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
项目类别：
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/8906883
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

项目摘要

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）：研究细胞内缩放的机制不同生物体之间以及同一生物体内不同组织类型和发育过程中的细胞大小差异很大，对细胞器和内部结构提出了不同的代谢和功能需求。一个基本问题是如何调节细胞核、有丝分裂纺锤体和染色体等重要的亚细胞成分以适应细胞大小的差异。爪蟾提供了两种生理环境，我们可以在其中研究这个问题。首先，我们可以将非洲爪蟾与较小的相关物种热带爪蟾进行比较，后者产下的卵较小，并且在整个发育过程中细胞比例也较小。其次，我们可以比较非洲爪蟾胚胎发生的不同阶段，直径约 1 毫米的卵迅速分裂形成更小的卵裂球，到第 15 次分裂时直径减小到 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物，在体外重现细胞器缩放，我们可以用它来识别大小变化背后的分子差异。我们的第一个具体目标集中在有丝分裂纺锤体上，我们利用计算机模拟来确定微管动力学和组织的参数，这些参数可能有助于物种之间和发育过程中纺锤体大小和形态的变化。该目标还开发了新方法，通过将纺锤体组装反应物理限制在不同尺寸的液滴内来检查外在缩放机制，这将揭示是否存在从外部缩放纺锤体或改变组装路径的尺寸阈值。目标 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，从而发生完全分离。在目标 3 中，我们通过研究非洲爪蟾发育过程中改变核大小的后果来开始解决细胞器缩放的重要性。这些实验将深入了解缩放如何发生以及如何促进细胞内形态发生和细胞分裂、生存和发育所必需的过程以及包括癌症在内的人类疾病的缺陷。