Signals in a Rapid Differentiation

快速分化的信号

• 批准号: 9307759
• 负责人: Chandler Fulton
• 金额: $ 9.5万
• 依托单位: Brandeis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1995-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9307759&HistoricalAwards=false
• 关键词: Signals; Rapid; Differentiation

9307759 Fulton The ultimate goal of this laboratory is to elucidate the orchestration of causal pathways during cell differentiation. The paradigm employed for this purpose is the 100-minute change of Naegleria gruberi from amoebae to flagellates--from one eukaryotic motility form to another--a differentiation that is exceptionally accessible for analysis except for lack of molecular genetics. The quest continues via three ongoing studies, each of interest separately but all converging toward the goal. 1) Surprisingly this quick change has two "checkpoints," at 10 min and at 20 min, at which the strength of some signal(s) is evaluated and decisions are made whether to progress toward differentiation or to "hold." Experiments are planned to define these checkpoints. 2) Certain conserved proteins are synthesized during differentiation in processes that involve signals regulating gene expression, mRNA stability, and localization of these proteins in flagella and associated organelles. These proteins include four calcium-binding proteins: a flagellar and a cell-body calmodulin, calcineurin B and centrin (a.k.a. caltractin), which becomes associated primarily with the basal bodies when these organelles form de novo during differentiation. Studies are continuing to define these calcium- binding proteins by examining gene expression, sequence, and protein localization. 3) The essential tool of DNA-mediated transformation of Naegleria is being developed using an homologous selectable marker, the OMP decarboxylase gene. The description of checkpoints and the study of conserved localized proteins is expected to yield results of immediate interest while the molecular genetic system is achieved. Once gene introduction is possible in Naegleria, the information from the first two aims will make it feasible to determine causal pathways for signals from initiation of differentiation to assembly of components into basal bodies and flagellae. %%% This research takes advantage of a unicellular organism, Naegleria gruberi, to study the principles involved in cellular differentiation. In response to chemical, mechanical, or physical changes in its environment, this organism, within one hundred minutes, can change from an ameba to an actively swimming, streamlined form with two flagellae. These two forms move by two very different mechanisms which involve very different sets of cellular machinery . This quick change represents an excellent model to study the biochemical signal pathways and changes in gene expression involved in a well-defined developmental process. The results should shed light on the mechanisms of cellular differentiation common to all living things, and will also expand our knowledge of the diversity of mechanisms by which a variety of organisms respond to environmental signals. ***

9307759富尔顿 该实验室的最终目标是阐明细胞分化过程中因果通路的编排。 用于此目的的范例是100分钟的变化，Naegleria gruberi从变形虫到鞭毛虫-从一种真核动力形式到另一种-除了缺乏分子遗传学之外，这种分化非常容易进行分析。 这一探索通过三项正在进行的研究继续进行，每项研究都各自感兴趣，但都朝着目标前进。 1)令人惊讶的是，这种快速变化有两个“检查点”，在10分钟和20分钟，在此评估一些信号的强度，并决定是向分化进展还是“保持”。" 实验计划定义这些检查点。 2)某些保守蛋白质在分化过程中合成，这些过程涉及调节基因表达、mRNA稳定性的信号以及这些蛋白质在鞭毛和相关细胞器中的定位。 这些蛋白质包括四种钙结合蛋白：鞭毛和细胞体钙调蛋白、钙调磷酸酶B和中心蛋白（也称为中心蛋白）。caltractin），当这些细胞器在分化过程中重新形成时，其主要与基体相关。 通过检测基因表达、序列和蛋白定位，研究人员正在继续对这些钙结合蛋白进行定义. 3)DNA介导的耐格里属转化的基本工具正在开发使用同源选择标记，OMP脱羧酶基因。 在建立分子遗传学系统的同时，对检查点的描述和保守定位蛋白质的研究有望产生直接的结果。 一旦基因导入耐格里属是可能的，从前两个目标的信息将使其可行的确定从分化开始到组装成基体和鞭毛的组件的信号的因果途径。 本研究利用一种单细胞生物--格鲁伯耐格里霉来研究细胞分化的原理。 为了应对环境中的化学、机械或物理变化，这种有机体可以在100分钟内从变形虫变成一种活跃的游泳，流线型的形式，有两个鞭毛。 这两种形式通过两种非常不同的机制移动，涉及非常不同的细胞机制。 这种快速的变化代表了一个很好的模型来研究生化信号通路和基因表达的变化，这些变化涉及一个明确的发育过程。 这些结果将有助于阐明所有生物共同的细胞分化机制，也将扩大我们对各种生物体对环境信号反应机制多样性的认识。 ***