Gene Expression Changes in Response to Aging Compared to Stress Conditions in Drosophila melanogaster

Gene expression changes in response to aging and stress conditions such as hyperoxia, heat stress and ionizing radiation were compared. The results show that a set of 18 genes, including the heat shock protein (Hsp) genes Hsp70, Hsp83 and l(2)efl, and the glutathione‐Stransferase gene GstD2,  were up‐regulated across all conditions, indicating a general stress response shared with aging. Quantitative PCR, Northern analysis and GstD‐GFP reporter constructs confirmed selected gene expression changes. While aging shared features with each stress, aging was more similar to the stresses most associated with oxidative stress than to heat stress. Aging is associated with down‐regulation of numerous mitochondrial genes, including electron‐transport‐chain (ETC) genes and mitochondrial metabolism genes, and a sub‐set of these changes was also observed upon hydrogen peroxide stress and ionizing radiation stress. The extensive down‐regulation of mitochondrial genes during aging is consistent with an aging‐associated failure in mitochondrial maintenance.