Understanding the role of tether proteins to maintain chromatin-nuclear lamina contacts in premature aging.

项目总结/摘要 这项建议概述了一项调查的作用，染色质拴系蛋白在维持外周血淋巴细胞， 异染色质和核纤层的完整性。已经确定异染色质与 核纤层在发育过程中起重要作用，并有助于维持所收养的细胞 命运纤层蛋白的基因突变，如在Hutchinson-Gilford早衰综合征（HGPS）中所见， 与核纤层形态改变和外周异染色质破坏有关。 然而，核纤层突变和异染色质定位之间的确切联系仍然不清楚。 我建议测试，如果染色质拴系蛋白PRR 14在这一过程中发挥了关键作用， 在过早衰老途径中发挥作用。我们的数据表明，PRR 14组织了一个显着的部分， 异染色质在核层。PRR 14缺乏导致外周异染色质脱离 而PRR 14过表达显著增加了异染色质的比例， 位于核外围。先前的研究结果表明PRR 14是一种表观遗传阻遏物，其缺失可以 释放转录基因沉默。此外，我们的研究结果表明，PRR 14的缺失导致细胞核分裂。 核纤层缺陷类似于在与核纤层突变相关的疾病中观察到的缺陷。在这里我们建议 研究PRR 14在维持核纤层染色质组织中的作用，并评估PRR 14在维持核纤层染色质组织中的作用。 核纤层突变通过PRR 14起作用，引起纤层相关染色质的失调。我们将 确定PRR 14缺失对核纤层异染色质组织的影响，并确定表观遗传 通过PRR 14标记核纤层定位的基因组区域的特征。此外，我们将确定如何 核纤层突变影响PRR 14在核纤层组织染色质中的功能， 早老蛋白（核纤层蛋白A蛋白的突变形式）影响PRR 14-核纤层相互作用并触发核纤层蛋白的表达。 纤层和外周异染色质缺陷。最后，为了确定PRR 14-核纤层结合是否是 受法尼基基团修饰的影响，我们将测试法尼基转移酶抑制剂是否能恢复 PRR 14在HGPS细胞中系留异染色质中的功能。我们的工作将提供关键的见解， 染色质与核纤层结合的基础知识。这将大大提高我们的 理解核纤层和基因组组织缺陷背后的分子机制， 核纤层蛋白病

Project Summary/Abstract This proposal outlines an investigation into the role of chromatin-tethering proteins in maintenance of peripheral heterochromatin and the integrity of nuclear lamina. It is well established that heterochromatin association with the nuclear lamina plays an important role in development, and contributes to maintenance of the adopted cell fate. Genetic mutations in lamina proteins, such as is seen in Hutchinson-Gilford progeria syndrome (HGPS), is associated with alterations in the morphology of the nuclear lamina and disruption of peripheral heterochromatin. However, the precise link between nuclear lamina mutations and heterochromatin positioning remains unclear. I propose to test if the chromatin-tethering protein PRR14 plays a critical role in this process and therefore functions in the premature aging pathway. Our data demonstrate that PRR14 organizes a significant fraction of heterochromatin at the nuclear lamina. Lack of PRR14 results in detachment of the peripheral heterochromatin from the nuclear lamina, while PRR14 overexpression substantially increases the fraction of heterochromatin located at the nuclear periphery. Previous findings implicate PRR14 as an epigenetic repressor and its loss can release transcriptional gene silencing. Furthermore, our results demonstrate that PRR14 loss results in nuclear lamina defects similar to those observed in diseases associated with nuclear lamina mutations. Here we propose to study the role of PRR14 in maintenance of chromatin organization at the nuclear lamina and assess how nuclear lamina mutations act through PRR14 to cause dysregulation of lamina-associated chromatin. We will determine the effect of PRR14 loss on heterochromatin organization at the nuclear lamina and define epigenetic features that mark genome regions for nuclear lamina localization via PRR14. Further, we will determine how nuclear lamina mutations affect the PRR14 function in organizing chromatin at the nuclear lamina by testing how Progerin (a mutant form of Lamin A protein) affects the PRR14-nuclear lamina interaction and triggers nuclear lamina and peripheral heterochromatin defects. Finally, to determine if PRR14-nuclear lamina association is affected by farnesyl group modification on Progerin, we will test whether farnesyltransferase inhibitors restore PRR14 function in tethering heterochromatin in HGPS cells. Our work will provide critical insights into the fundamental knowledge of chromatin association with the nuclear lamina. This would significantly advance our understanding of molecular mechanism behind nuclear lamina and genome organization defects observed in laminopathy diseases.