Activation of Endogenous Transposable Elements by Myc During Aging

衰老过程中 Myc 激活内源转座元件

• 批准号: 10152481
• 负责人: NICOLA NERETTI
• 金额: $ 33.52万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10152481
• 关键词: Adult; Affect; Age; Aging; Animal Model; Animals; Binding; Cell Nucleus; Cells; Cellular Stress; ChIP-seq; DNA; DNA Binding; DNA Damage; DNA Insertion Elements; DNA Transposable Elements; Data; Data Set; Drosophila genus; Embryo; Event; Frequencies; Future; Genes; Genome; Genomic Instability; Genomics; Goals; Heterochromatin; Human; Individual; Induced Mutation; Insertional Mutagenesis; Intervention; Life; Link; Longevity; Malignant Neoplasms; Mammals; Maps; Mediating; Methodology; Methods; Midgut; Mining; Mobile Genetic Elements; Modeling; Muscle; Mushroom Bodies; Neurons; Oncoproteins; Organism; Pathway interactions; Phenotype; Positioning Attribute; Process; Proto-Oncogene Proteins c-myc; Publishing; RNA Interference; Regulation; Site; Somatic Cell; Study models; Testing; Time; Tissues; Transcript; Transgenes; age related; aging gene; base; brain cell; cell type; fly; genetic approach; genome sequencing; genome-wide analysis; healthspan; improved; innovation; insight; novel; novel therapeutics; overexpression; stem cells; tumorigenesis; whole genome

! A poorly explored potential contributor to aging is the mobilization of endogenous transposable elements (TEs), which can be highly mutagenic and promote genomic instability. The goal of this proposal is to determine the functional link between activation of endogenous TEs by the transcription factor Myc and changes to lifespan and aging. Previous data showed that increasing or decreasing levels of the oncoprotein Myc in the model organism Drosophila reduced or extended lifespan, respectively. New data that forms the basis of this proposal show that Myc activates the expression of a subset of endogenous TEs. Because mobilization of TEs can cause insertional mutagenesis, genome rearrangements and DNA damage, they have been proposed to contribute to tumorigenesis and other phenotypes associated with aging. However, a significant hurdle to understanding the effects of transposon mobilization has been a lack of methods to identify de novo TE insertions, since they are unique to individual somatic cells so are extremely difficult to identify by sequencing bulk tissue DNA. Only a single cell approach such as the one described in this proposal allows the number and distribution of de novo TE insertions that occur with age in somatic cells to be determined. Significantly, whole genome sequencing of multiple individual indirect flight muscle (IFM) nuclei from young and old wildtype flies revealed that the number of de novo transposon insertions increased with age. The three most frequently mobilized TEs were also found to be induced by Myc. However key questions remain unanswered regarding the link between Myc levels, TE activation and aging. For example, it is not known where TEs insert within the genome during aging or the frequency at which they mobilize. Nor is it known how Myc activates the expression of a subset of TEs, or whether their activation is functionally important for aging. The central hypothesis of this proposal is that is that Myc acts as a pro-aging gene by increasing and/or altering the distribution of de novo TE insertions in somatic cells, and that this adversely affects cell and tissue function leading to decreased lifespan. This hypothesis will be tested by pursuing three specific aims: Aim 1) Compare the frequency and genomic distribution of de novo TE insertions in wildtype flies and flies with increased or decreased Myc levels. Aim 2) Define the mechanism by which Myc activates the expression of specific TEs. Aim 3) Determine the functional link between Myc levels, TE activation and changes to lifespan. These analyses are significant because the activation of TEs by Myc could contribute to a range of age-related phenotypes, and suppressing their mobilization may provide a new therapeutic avenue to improve healthspan. The approach is methodologically innovative because it uses novel single cell genomic analyses to identify low abundance TE insertions that cannot be detected using whole tissue or organism approaches. It is conceptually innovative because interventions are tested that will for the first time define the functional contribution of de novo TE insertions to aging.

! 一个探索不足的潜在贡献者老化是动员内源性转座因子 (TEs)其可以是高度致突变的并且促进基因组不稳定性。本提案的目的是 确定转录因子Myc激活内源性TE与 寿命和衰老的变化。以前的数据表明，增加或减少癌蛋白的水平， Myc在模式生物果蝇中分别减少或延长寿命。新数据构成了 该提议的基础表明，Myc激活内源性TE的一个子集的表达。因为 TE的移动可引起插入突变、基因组重排和DNA损伤，它们具有 被认为有助于肿瘤发生和其他与衰老相关的表型。但 理解转座子动员作用的一个重要障碍是缺乏识别转座子动员作用的方法。 从头TE插入，因为它们对于个体体细胞是独特的，所以极难通过 测序大量组织DNA。只有单细胞方法，如本提案中描述的方法，才允许 待确定的体细胞中随年龄发生的从头TE插入的数量和分布。 值得注意的是，来自年轻人的多个个体间接飞行肌（IFM）细胞核的全基因组测序 而年老的野生型果蝇揭示了从头转座子插入的数量随着年龄的增长而增加。三 还发现最频繁移动的TE由Myc诱导。然而，关键问题仍然存在 关于Myc水平，TE激活和衰老之间的联系尚未回答。例如，不知道 其中TE在老化期间插入基因组中或它们移动的频率。也不知道是怎么回事 Myc激活一个TE子集的表达，或者它们的激活是否对衰老具有重要的功能。 该提议的中心假设是Myc作为促衰老基因通过增加和/或抑制衰老而起作用。 改变体细胞中从头TE插入的分布，并且这对细胞和组织产生不利影响 导致寿命缩短。这一假设将通过追求三个具体目标来检验：目标1） 比较野生型果蝇和果蝇中从头TE插入的频率和基因组分布， 增加或降低Myc水平。目的2）定义Myc激活以下表达的机制： 具体的TE。目的3）确定Myc水平、TE激活和寿命变化之间的功能联系。 这些分析是有意义的，因为Myc对TE的激活可能有助于一系列与年龄相关的疾病。 表型，并抑制其动员可能提供一种新的治疗途径，以改善健康。 这种方法在方法上是创新的，因为它使用了新的单细胞基因组分析来识别低 丰度TE插入不能使用整个组织或生物体方法检测。是 概念上的创新，因为干预措施进行了测试，将首次定义功能 TE重新插入对老化的贡献。