Mechanisms of Steroid-Triggered Programmed Cell Death

类固醇触发的程序性细胞死亡的机制

• 批准号: 6900748
• 负责人: CARL S. THUMMEL
• 金额: $ 17.19万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6900748
• 关键词: Drosophilidae; antibody; apoptosis; arthropod genetics; biological signal transduction; chromatin immunoprecipitation; developmental genetics; ecdysone; gene complementation; gene deletion mutation; genetic mapping; genetic regulation; genetic regulatory element; genetic screening; genetic transcription; genetically modified animals; green fluorescent proteins; guinea pigs; hormone regulation /control mechanism; laboratory rat; metamorphosis; methane sulfonate; point mutation; salivary glands; transcription factor

Small lipophilic hormones, acting through their corresponding nuclear receptors, control a wide range of developmental and physiological responses in higher organisms. Although extensive studies have focused on the mechanisms by which nuclear receptors control target gene transcription, relatively little is known about how a hormonal signal is transduced into an appropriate biological response during development. We propose to define one such pathway in detail - steroid-triggered cell death - using Drosophila as a model system. It is well known that steroids play a central role in controlling cell death in higher organisms, including humans. Only in Drosophila, however, has a genetic cascade been identified that links the hormone to a death response - the destruction of the larval salivary glands in response to the steroid hormone ecdysone during metamorphosis. We propose to build off this foundation, using an open-ended genetic screen to identify key players in this pathway. By using GFP as a marker for salivary glands in living animals, we will identify mutants that show specific defects in the steroid-triggered death response. A pilot screen has demonstrated the feasibility of this approach. We identified known genes in the death pathway as well as several new players, including genes that encode the CBP transcriptional co-factor and the TBP-related factor, TRF2. We propose to characterize these two genes in detail, defining the mechanisms that link them to cell death. We also propose to expand our search for death regulators through saturation mutagenesis of approximately 40% of the genome. Mutations will be mapped to specific genes, and functions for these genes will be assigned. This work provides a basis for understanding the molecular mechanisms of hormone signal transduction - defining the players in a genetic cascade that link the hormone to a stage- and tissue-specific biological response during development. This work also represents the first attempt to use random mutagenesis to dissect an endogenous programmed cell death response in Drosophila, raising the possibility that we will uncover novel death regulators. Finally, our studies provide a foundation for determining how steroids control cell death in humans, with implications for understanding and treating human disease.

小的亲脂激素通过其相应的核受体作用，控制着较高的生物体中广泛的发育和生理反应。尽管广泛的研究集中在核受体控制靶基因转录的机制上，但对在发育过程中如何将激素信号转化为适当的生物学反应的机制知之甚少。我们建议使用果蝇作为模型系统来详细定义一种这样的途径 - 类固醇触发的细胞死亡。众所周知，类固醇在控制包括人类在内的较高生物体中的细胞死亡中起着核心作用。然而，只有在果蝇中，才发现了与激素联系起来的遗传级联 死亡反应 - 变态过程中幼虫唾液腺的破坏是对类固醇激素ecdysone的响应。我们建议使用开放式的遗传屏幕来识别此途径中的关键参与者。通过将GFP用作活动物中唾液腺的标记，我们将确定突变体在类固醇触发的死亡反应中显示出特定缺陷。试点屏幕证明了这种方法的可行性。我们确定了死亡途径中的已知基因以及几个新参与者，包括编码CBP转录副因素和与TBP相关因素的基因，即 TRF2。我们建议详细描述这两个基因，以定义将它们与细胞死亡联系起来的机制。我们还建议通过大约40％的基因组的饱和诱变扩大对死亡调节剂的搜索。突变将映射到特定基因，并将这些基因的功能分配。这项工作为理解激素信号转导的分子机制提供了一个基础 - 定义了遗传级联的参与者，该基因级联反应将激素与发育过程中的阶段和组织特异性生物学反应联系起来。这项工作还代表了首次使用随机诱变来剖析果蝇中内源性编程的细胞死亡反应的尝试，从而提高了我们会发现新颖的死亡调节剂的可能性。最后，我们的研究为确定类固醇如何控制人类的细胞死亡提供了基础，对理解和治疗人类疾病产生了影响。