The regulation of cell death in vivo

描述(由申请人提供)：细胞在多细胞生物体的整个生命周期中死亡，从最早的发育阶段到成年生命，对细胞死亡的正确调控对生物体的健康至关重要。我们建议将两个实验室的互补专业知识结合在一起，这两个实验室的研究重点是体内细胞死亡的调控，使用果蝇模型系统。这些实验室带来了独特的工具和新的方法来研究果蝇细胞死亡调节器的复杂激活。这些调节者：收割者、HID、严峻和镰刀，聚集在一个基因复合体中。值得注意的是，这个复合体中的调控区域比单个基因更高度保守，在功能上也更重要。在这个提案中，我们关注的是这个基因组区域的转录、表观遗传和构象变化，这些变化是启动细胞死亡所必需的。我们已经开发了新的工具和方法来确定来自发育途径的输入如何整合来调节细胞死亡，以及染色质构象如何有助于启动细胞死亡。我们将检验这一假设，即染色质构象的变化确保了促凋亡基因在注定要死亡的细胞中的强劲表达，而在注定要存活的细胞中却强烈地阻止了表达。我们将研究三维染色质相互作用在这种对不同内在和外在信号做出反应的特定基因组合的快速和精确调节中的作用。我们还将确定细胞死亡途径的反馈是否对维持细胞死亡基因的激活很重要。大量的初步数据表明，这些研究将取得成功。在大规模的基因筛查中，我们已经确定了精确的细胞子集生理性死亡所需的基因。这些包括序列特定的转录调节因子，以及对染色质构象和三维染色体结构重要的基因。我们将研究这些基因如何激活细胞死亡基因复合体。在这项资助结束时，我们将开发出一个控制生理性细胞死亡的功能验证模型。此外，我们还将描述基因复合体和共享调控区调控的一般原则。

DESCRIPTION (provided by applicant): Cells die throughout the lifespan of multicellular organisms, and the correct regulation of cell death is critical for organismal health, from the earliest stages of development through adult life. We propose to bring together the complementary expertise of two labs whose research has focused on the regulation of cell death in vivo, using the Drosophila model system. These labs bring unique tools and novel approaches to study the complex activation of the Drosophila cell death regulators. These regulators: reaper, hid, grim and sickle, are clustered together in a gene complex. Remarkably, the regulatory regions in this complex are more highly conserved, and are functionally more important, than the individual genes. In this proposal, we focus on transcriptional, epigenetic and conformational changes in this genomic region that are required to initiate cell death. We have developed new tools and approaches to determine how the input from developmental pathways is integrated to regulate cell death, and how chromatin conformation contributes to the initiation of cell death. We will test the hypothesis that changes in chromatin conformation ensure robust expression of pro- apoptotic genes in cells fated to die, while strongly blocking expression in cells destined to live. We will examine the role of three dimensional chromatin interactions in this rapid and precise regulation of specific combinations of genes in response to different intrinsic and extrinsic signals. We will also determine whether feedback from the cell death pathway is important for the maintenance of cell death gene activation. Extensive preliminary data indicate that these studies will be successful. In a large-scale genetic screen, we have identified genes that are required for the physiologic death of a precise subset of cells. These include sequence specific transcriptional regulators, and genes important for chromatin conformation and three dimensional chromosome architectures. We will investigate how these genes activate the cell death gene complex. At the conclusion of this grant, we will have developed a functionally validated model of the control of physiologic cell death. In addition, we will have described general principles for the regulation of gene complexes and shared regulatory regions.