Transcriptional reprogramming in response to environmental cues: role of productive RNA polymerase II transcript elongation

响应环境线索的转录重编程：生产性 RNA 聚合酶 II 转录延伸的作用

• 批准号: 514058844
• 负责人: Professor Dr. Klaus Grasser
• 金额: --
• 依托单位: Lehrstuhl für Zellbiologie und Pflanzenbiochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/514058844?language=en
• 关键词: Transcriptional; reprogramming; response; environmental; cues

The genomic DNA of eukaryotic organisms is packaged into a nucleoprotein structure termed chromatin, and nucleosome particles represent the basic unit of chromatin. Hence, by restricting the accessibility of DNA nucleosomes repress various DNA-dependent processes such as gene transcription. Accordingly, RNA polymerase II (RNAPII), the enzyme that transcribes protein-coding genes (synthesising mRNAs), requires different assistant factors, which facilitate productive transcript elongation of DNA templates assembled into nucleosomes. Among the proteins that promote the elongation phase of RNAPII transcription are the so-called transcript elongation factors (TEFs). They represent a heterogeneous group of proteins with diverse functions including modulating the catalytic properties of RNAPII or destabilising nucleosomes in the path of the enzyme, allowing efficient mRNA synthesis. In line with their function in gene transcription TEFs contribute to adjusting accurately cellular transcript levels, thus modulating various stages of development.Using the Arabidopsis plant model, we have recently started investigating the involvement of TEFs in plant responses to environmental cues. Our preliminary analyses revealed that compared to controls, mutant plants deficient in certain TEFs exhibited distinct defects in their response to stressful conditions. Changing circumstances require (relatively rapid) transcriptional reprogramming that apparently is especially demanding for the RNAPII elongation machinery. Therefore, we propose provoking transcriptional reprogramming induced by environmental stress as a tool to study the functionality of TEFs in a meaningful biological context. We intend to assay mutants deficient in various TEFs upon exposure to a set of stress conditions (e.g. heat, cold, drought) to challenge RNAPII elongation. Employing genome-wide analyses (transcriptomics, chromatin immunoprecipitation in combination with nucleosome position/stability assays) we intend to characterise the molecular contribution of different TEFs in plant responses to abiotic stress conditions. In conclusion, the proposed project will provide novel insight into the action of TEFs in transcriptional reprogramming. Beyond that it will complement a more complete understanding of plant responses to environmental stress, which is also relevant in the light of progressing climate change.

真核生物的基因组DNA被包装成称为染色质的核蛋白结构，核小体颗粒代表染色质的基本单位。因此，通过限制DNA的可及性，核小体抑制各种DNA依赖性过程，如基因转录。因此，RNA聚合酶II（RNAPII），转录蛋白质编码基因（合成mRNA）的酶，需要不同的辅助因子，其促进组装成核小体的DNA模板的生产性转录延长。在促进RNAPII转录的延伸阶段的蛋白质中，有所谓的转录物延伸因子（TEF）。它们代表了一组具有不同功能的蛋白质，包括调节RNAPII的催化特性或在酶的路径中使核小体不稳定，从而允许有效的mRNA合成。TEFs在基因转录中的功能是精确地调节细胞转录水平，从而调节发育的各个阶段，我们最近以拟南芥为模型，开始研究TEFs在植物对环境信号反应中的作用。我们的初步分析表明，与对照相比，在某些TEFs缺陷的突变体植物表现出明显的缺陷，在他们的压力条件下的反应。不断变化的情况下，需要（相对快速）转录重编程，显然是特别要求RNAPII延长机制。因此，我们建议激发环境应激诱导的转录重编程，作为在有意义的生物学背景下研究TEF功能的工具。我们打算在暴露于一组胁迫条件（例如热、冷、干旱）以挑战RNAPII延伸时测定各种TEF缺陷的突变体。采用全基因组分析（转录组学，染色质免疫沉淀与核小体位置/稳定性测定相结合），我们打算研究不同TEF在植物对非生物胁迫条件的反应中的分子贡献。总之，拟议的项目将提供新的洞察TEFs在转录重编程的行动。除此之外，它还将补充对植物对环境胁迫的反应的更完整的理解，这也与气候变化的进展有关。