Control of Gene Expression and Life Span

描述(申请人提供)：这项提案的重点是确定染色质随年龄的变化如何导致衰老的有害后果，并开发新的遗传和药物干预措施，通过影响更年轻的染色质状态来延长健康寿命。随着年龄的增长，抑制性异染色质减少，转座元件(TES)的表达和动员增加。我们假设TES的表达和动员有助于衰老和年龄相关的疾病，并建议利用通常抑制TES表达和扩张的细胞系统之一--结构性抑制性异染色质，以维持TES的沉默，促进更长、更健康的寿命。我们将使用影响寿命的全基因组方法和干预措施，包括饮食限制(DR)，以及预计将维持抑制性异染色质的干预措施，以建立染色质状态、TE表达和转位与寿命之间的关系。我们将利用esiRNA RISC途径，天然地抑制TE的表达和动员，以便直接测试TE活性的抑制是否是长寿的重要组成部分。这一建议的目的是检验以下假设：(I)与年龄相关的抑制性异染色质减少导致TE活性增加；(Ii)延长寿命的干预措施维持抑制性异染色质，从而防止TE活性增加；(Iii)增加抑制性异染色质的干预措施降低TE活性并延长寿命；以及(Iv)抑制TE表达和TE动员是决定长寿的重要因素。为了更好地了解TE活性、抑制TE活性的细胞机制和长寿之间的关系，以及确定能够延长健康寿命的新的染色质相关途径，我们将：(1)使用RNA-SEQ、基因组深度测序、CHIP-SEQ(H3K9me2、H3K9Me3、HP1)和FIRE-SEQ，测试随着年龄的增长，与TE表达增加相关的抑制性异染色质的丢失，以及包括DR在内的延长寿命的干预措施，恢复抑制性异染色质和抑制TE活性；(2)使用已知的与年龄相关的维持或增加抑制性异染色质的分子遗传操作来测试TE表达和动员的减少是否会延长寿命；(3)确定esiRNA途径(Dice-2、Ago2和R2D2)的活性如何随年龄和延长寿命的干预措施而改变；以及(4)使用分子遗传学工具直接改变esiRNA途径的活性来影响TE的表达和动员，以确定这些操作对正常衰老和延长寿命干预措施的结果的影响。

DESCRIPTION (provided by applicant): The focus of this proposal is to determine how changes in chromatin with age contribute to the deleterious consequences of aging, and to develop new genetic and pharmacological interventions that extend healthy life span by effecting a more "youthful" chromatin state. With age, repressive heterochromatin decreases, and both expression and mobilization of transposable elements (TEs) increase. We hypothesize that expression and mobilization of TEs contributes to aging and age-related disorders, and propose to exploit one of the cellular systems that normally suppresses TE expression and expansion, constitutive repressive heterochromatin, in order to maintain silencing of TEs and promote a longer, healthier life. We will use genome-wide approaches and interventions that affect life span, including Dietary Restriction (DR), and interventions predicted to maintain repressive heterochromatin, in order to establish the relationship between chromatin states, TE expression and transposition, and longevity. We will utilize the esiRNA RISC pathway that naturally suppresses TE expression and mobilization, in order to test directly whether repression of TE activity is an important component of longevity. The aims of this proposal are to test the hypotheses that: (i) age-related decreases in repressive heterochromatin lead to increased TE activity; (ii) interventions that extend life span maintain repressive heterochromatin, thereby preventing increases in TE activity; (iii) interventions that increase repressive heterochromatin reduce TE activity and extend life span; and (iv) repression of TE expression and TE mobilization are important elements in longevity determination. To better understand the relationship between TE activity, the cellular mechanisms that repress it, and longevity, as well as to identify new chromatin-related pathways that can extend healthy life span, we will: (1) use RNA-seq, genomic deep-sequencing, ChIP-seq (H3K9me2, H3K9Me3, HP1) and FAIRE-seq, to test that with age there is a loss of repressive heterochromatin that is associated with increased TE expression, and that life span-extending interventions, including DR, restore repressive heterochromatin and suppress TE activity; (2) use molecular genetic manipulations known to maintain or increase repressive heterochromatin with age to test that a reduction of TE expression and mobilization will extend life span; (3) determine how the activity of the esiRNA pathway (Dicer-2, Ago2 and R2D2) is altered with age and in life span-extending interventions; and (4) use molecular genetic tools to directly alter the activity of the esiRNA pathway to affect TE expression and mobilization, in order to determine the effects of these manipulations on normal aging and on the outcome of life span-extending interventions.