Characterization of how mRNA translation influences reproductive aging

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Summary Aging represents a major risk factor for a broad range of diseases and declines in tissue homeostasis and function. This is particularly true in the female reproductive system where the aging of stored oocytes has been directly linked with an increased incidence of miscarriages and birth defects. Our long-term goal is to identify and characterize the factors that contribute to reproductive aging. In mammals, eggs can be stored months, years, or decades, making the analysis of reproductive aging slow and experimentally difficult. Here, we seek to build upon previous efforts to establish the Drosophila ovary as a powerful system with which to study reproductive aging. Interestingly, the decline in egg quality has been correlated with lower levels of mRNA translation across species, from flies to humans. Despite this common defect, we know surprisingly little about the mechanisms responsible for this reduction of mRNA translation capacity within stored eggs. Here, we propose to use state of the art genetic manipulation and biochemical analysis to systematically characterize how the machinery required for mRNA translation changes with maternal age and during egg storage in Drosophila. Moreover, we seek to genetically test whether manipulating ribosome levels and translation initiation/elongation rates prolongs the quality of stored eggs. We have established an operational pipeline for conducting all the experiments outlined under this proposal and seek to take advantage of a number of innovative tools and techniques that have been adopted by our group. Under Aim 1, we will use complementary molecular and biochemical approaches to comprehensively characterize the extent to which protein synthesis and ribosome levels changes in the ovaries of aging females and in eggs stored over two weeks. We will also use biochemical and innovative reporter based assays to evaluate whether translation fidelity declines with age. In aim 2, we will test the extent to which increasing or decreasing ribosome levels and translation initiation and elongation rates improves the quality of stored eggs. Under aim 3, we will characterize how the ribosome oxygenase NO66 influences egg quality. We believe this comprehensive analysis of in vivo oocytes during the course of aging will provide key insights into why the quality of eggs declines with age and will reveal new molecular targets for the development of therapies designed to improve and extend reproduction. Given our focus on the role ribosomes play in this process, we believe our work will broadly impact the study of tissue homeostasis and regeneration in aging organisms.