Genomic Regulation at the Nuclear Periphery

描述（由申请人提供）： 一百多年来，科学家们已经观察到细胞核内染色体组织的空间偏好。虽然我们现在已经破译了从酵母到人类的真核生物物种的整个基因组序列，但这些基因组如何在物理上组织以支持基因组功能仍然是一个悬而未决的问题。在过去的几年里，在酵母和哺乳动物模型中的几项研究表明，基因与核外围的关联，可能与内核膜蛋白，起着调节转录的作用。这些研究的重要性被以下发现所强调：几种人类疾病与包括emerin在内的完整的内核膜蛋白内的突变有关，这导致Emery-Dreifuss肌营养不良症（EDMD）。然而，设计治疗策略极具挑战性，因为在核周边如何影响转录的两个关键问题上仍然存在大量混乱：1）在酵母中，与核周边的关联似乎激活了一些基因，同时抑制了其他基因，以及2）异源驱动报告基因到周边是否足以诱导哺乳动物细胞中的转录抑制仍然存在争议。在这个提议中，我们的策略是在两个酵母模型中推导出全基因组范围的染色质-内核膜相互作用的图谱，S。cerevisiae和S. pombe（目标1）。这些生物显示80%的蛋白质编码基因的对应性，而缺乏显着的同线性;我们可以利用这些特性来识别基因（以及它们所贡献的调控途径）与保守的位点的内核膜协会，我们预测将反映功能的重要性。在目标2中，我们将研究调控刺激如何改变基因与核外围的关联，评估这些基因调控中对特定内核膜蛋白的需求，并测试工程和可逆系链在核外围重演基因调控的能力。我们的长期目标是了解我们如何改善由内核膜蛋白突变引起的转录组变化，并建立范式，使我们能够制定策略来解决越来越多的遗传疾病，包括EDMD，这些疾病统称为“核分裂症”。

DESCRIPTION (provided by applicant): For over one hundred years, scientists have observed spatial preferences for the organization of the chromosomes within the nucleus. While we have now deciphered the entire genome sequences of eukaryotic species from yeasts to humans, how those genomes are physically organized to support genomic functions remains an open question. Within the last few years, several studies in yeast and mammalian models have suggested that association of genes with the nuclear periphery, likely with inner nuclear membrane proteins, acts to regulate transcription. The importance of these studies is underscored by the discovery that several human diseases are associated with mutations within integral inner nuclear membrane proteins including emerin, which causes Emery-Dreifuss Muscular Dystrophy (EDMD). Treatment strategies are extremely challenging to devise, however, since there remains substantial confusion over two key issues of how the nuclear periphery influences transcription: 1) in yeast, association with the nuclear periphery appears to activate some genes while repressing others, and 2) it remains controversial whether heterologously driving a reporter gene to the periphery is sufficient to induce transcriptional repression in mammalian cells. In this proposal, our strategy is to derive genome-wide maps of chromatin-inner nuclear membrane interactions in two yeast models, S. cerevisiae and S. pombe (Aim 1). These organisms display correspondence of 80% of their protein coding genes while lacking significant synteny; we can leverage these properties to identify genes (and the regulatory pathways they contribute to) with conserved sites for inner nuclear membrane association, which we predict will reflect functional importance. In Aim 2, we will examine how regulatory stimuli alter the association of genes with the nuclear periphery, assess the requirement for specific inner nuclear membrane proteins in the regulation of these genes, and test the ability of engineered and reversible tethers to recapitulate gene regulation at the nuclear periphery. Our long-term goal is to understand how we might ameliorate the changes in the transcriptome that result from mutations in inner nuclear membrane proteins, and establish paradigms to allow us to devise strategies to tackle a growing number of genetic diseases including EDMD, which are collectively called "nuclear envelopathies".