Collaborative Research: Integration of metabolic cues and life cycle decisions in Chlamydomonas

合作研究：衣藻代谢线索和生命周期决策的整合

• 批准号: 1515169
• 负责人: Christoph Benning
• 金额: $ 70万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1515169&HistoricalAwards=false
• 关键词: Collaborative; Research; Integration; metabolic; cues

Single-celled organisms, such as protists and bacteria, inhabit fluctuating environments where nutrient availability isn't always guaranteed. To cope with this "feast or famine" uncertainty, cells have evolved processes that allow them to respond appropriately by growing and dividing when nutrients are present (proliferation), or by becoming dormant and adopting an energy-conserving state when starved (quiescence). This project utilizes a single-celled reference organism, the green alga Chlamydomonas, to investigate how molecular switches that govern proliferation and quiescence are controlled and how they are coordinated to ensure that they don't interfere with each other. Microorganisms like these can accumulate large quantities of valuable compounds, e.g. oils, but only when starved. It is anticipated that knowledge about the molecular switches governing transitions between the states of proliferation and quiescence will allow predictions about how these states can be controlled and engineered. Thus, newly discovered details about these molecular switches provide potential engineering strategies to uncouple high yields of valuable compounds from starvation responses. Students and postdoctoral fellows from the two research locations will collaborate to identify and model the interactions between key regulators of quiescence and proliferation that have counterparts in many other species including plants and animals. The diversity of approaches and quantitative training components prepare the trainees for science careers in industry or academia. The long term goal of this project is to gain a predictive understanding of how nutrient and metabolic cues are integrated into coherent decisions that control life cycle state transitions. In the unicellular green alga Chlamydomonas reinhardtii, two nuclear protein complexes, CHT7-C and RB-C, have been identified that govern the transitions between nutrient-deprivation induced quiescence, cell growth, and commitment to cell division. It is hypothesized that the quiescence regulator CHT7-C, and the cell cycle commitment regulator RB-C form an interlocking transcriptional network that coordinately controls cell growth and division responses to nutrient or metabolic cues. The objectives of this project are to: (1) characterize purified CHT7-C and RB-C complexes in order to define their subunit composition and modifications under different life cycle states; (2) Identify CHT7-C and RB-C target genes followed by generation of a transcriptional network model to observe common nodes that functionally couple the two complexes; (3) combine mutations affecting different components of the two complexes into isogenic lines to obtain synthetic phenotypes that provide insights into function and interrelation of the two complexes in vivo; and (4) build a testable logic switch model and develop quantitative markers to test and revise the model. The collaborative approach taken for studying the interactions between quiescence and cell proliferation regulators is aimed at transforming the understanding of the networks that establish and maintain coordinated global responses to metabolic and nutritional cues.

单细胞生物，如原生生物和细菌，居住在波动的环境中，营养供应并不总是得到保证。为了科普这种“盛宴或饥荒”的不确定性，细胞进化出了一些过程，使它们能够在营养物质存在时（增殖）通过生长和分裂做出适当的反应，或者在饥饿时（静止）通过休眠并采取节能状态。本项目利用单细胞参考生物，绿色衣原体，研究如何控制增殖和静止的分子开关，以及它们如何协调，以确保它们不会相互干扰。像这样的微生物可以积累大量有价值的化合物，例如油，但只有在饥饿的时候。预计有关控制增殖和静止状态之间转换的分子开关的知识将允许预测如何控制和设计这些状态。因此，新发现的关于这些分子开关的细节提供了潜在的工程策略，从饥饿反应中解偶联高产量的有价值的化合物。来自这两个研究地点的学生和博士后研究员将合作识别和模拟静止和增殖的关键调控因子之间的相互作用，这些调控因子在包括植物和动物在内的许多其他物种中都有对应物。方法的多样性和定量培训内容为受训者在工业或学术界从事科学职业做好准备。该项目的长期目标是获得营养和代谢线索如何整合到控制生命周期状态转换的连贯决策中的预测性理解。在单细胞的绿色衣藻莱茵衣藻，两个核蛋白复合物，CHT 7-C和RB-C，已被确定为支配营养剥夺诱导的静止，细胞生长，并致力于细胞分裂之间的过渡。假设静止调节因子CHT 7-C和细胞周期定型调节因子RB-C形成一个互锁的转录网络，协调控制细胞生长和对营养或代谢线索的分裂反应。本研究的主要目的是：（1）鉴定纯化的CHT 7-C和RB-C复合物，以确定它们在不同生命周期状态下的亚基组成和修饰;（2）鉴定CHT 7-C和RB-C靶基因，然后建立转录网络模型，观察两种复合物在功能上偶联的共同节点;（3）将影响两种复合物的不同组分的联合收割机突变组合成等基因系，以获得合成表型，其提供对两种复合物在体内的功能和相互关系的了解;（4）建立一个可测试的逻辑开关模型，并开发定量指标对模型进行检验和修正。研究静止和细胞增殖调节剂之间的相互作用所采取的合作方法旨在改变对建立和维持协调的全球代谢和营养线索反应的网络的理解。