Characterization and genetic analysis of aging in Daphnia

描述(申请人提供)：该项目将开发微型甲壳类水蚤作为衰老生物学的模型系统。水蚤是一种淡水微型甲壳动物，通过周期孤雌生殖进行繁殖，使实验室研究人员能够轻松地产生数千个基因相同的个体。用于量化寿命和老龄化速度遗传变异的生物统计学和生理学方法将与全基因组基因表达和转基因个体的发育分析相结合。目标是建立一个模型系统，其中关于老龄化的信息可以从分子、细胞、生理和人口学方法综合起来，并放在已知的对老龄化施加的生态压力和对现有资源的反应的背景下。建议的工作包括A)表征TCO中的衰老，其整个基因组已被测序；B)表征来自野外的新分离物的遗传多样性集合中的衰老；C)描述TCO克隆和新分离物对饮食限制的反应；D)应用全基因组微阵列技术来量化TCO和新分离物中依赖年龄的基因表达的全球模式；E)调查饮食限制引起的依赖于年龄的基因表达变化的规模和模式；F)鉴定具有年龄依赖性调节或其表达可预测寿命的新基因和新途径，(G)开发一种活体水蚤的遗传转化技术，H)参与调节限制饮食对衰老影响的已知途径中的关键基因的过度表达，以及i)观察关键基因过度表达的水蚤克隆的衰老和对限制饮食的反应。 与公共卫生相关：老龄化是指随着个人年龄的增长，身体机能的逐渐下降。了解衰老生物学的新模式生物的发展使人们能够更广泛地了解潜在干预措施的遗传机制和后果，例如限制饮食，以减少衰老的负面影响。在这项工作中，通过鉴定不同衰老速率的遗传变异，鉴定与年龄相关的表达基因，以及确定关键基因对衰老过程的影响，开发了一种新的模式生物--水蚤。

DESCRIPTION (provided by applicant): This project will develop the microcrustacean Daphnia as a model system for the biology of aging. Daphnia are freshwater microcrustaceans that reproduce through cyclic parthenogenesis, allowing laboratory investigators to generate thousands of genetically identical individuals easily. Biodemographic and physiological methods for quantifying genetic variation of lifespan and rates of aging will be coupled with analyses of genome-wide gene expression and the development of transgenic individuals. The goal is to establish a model system where information on aging can be integrated from molecular, cellular, physiological and demographic approaches and placed in the context of known ecological pressures exerted on aging and on the response to available resources. The proposed work includes A) characterization of aging in TCO, the Daphnia pulex clone whose entire genome has been sequenced, B) characterization of aging in a genetically diverse collection of new isolates from the field, C) characterization of the response to dietary restriction in the TCO clone and new isolates, D) application of whole-genome microarray technology to quantify global patterns of age-dependency in gene expression in TCO and new isolates, E) investigation of the scale and pattern of changes in age-dependent gene expression induced by dietary restriction, F) identification of novel genes and pathways with age- dependent regulation or whose expression is predictive of lifespan, G) development of a technique for heritable transformation of live Daphnia, H) overexpression of key genes involved in pathways known to regulate the effects of dietary restriction on aging, and I) observation of aging and response to dietary restriction in Daphnia clones where key genes have been overexpressed. PUBLIC HEALTH RELEVANCE: Aging is the progressive decline of bodily faculties as individuals grow older. The development of new model organisms to understand the biology of aging allows for a broader understanding of the genetic mechanisms and consequences of potential interventions, such as dietary restriction, that reduce the negative effects of aging. In this work, a new model organism, Daphnia, is developed through the identification of genetic variants with different rates of aging, identification of genes with age-dependent expression, and determination of the effects of key genes on aging processes.