Aging induces de novo rhythmic expression of oxidative stress-responsive genes

Disruption of the circadian clock, which directs rhythmic expression of numerous genes, accelerates aging. To inquire how the circadian system protects organisms during aging, we compared circadian transcriptomes in heads of young and old Drosophila melanogaster. These data revealed a class of genes that adopt de novo rhythmicity during aging, termed "late life cyclers" (LLCs). We show that application of exogenous oxidative stress in young flies mimics aging by inducing robust, rhythmic LLC upregulation in a light- and CLOCK-dependent fashion. Additionally, we identified age-onset rhythmicity in some primary piRNA transcripts that overlap antisense transposable elements. To share our data, we developed a database for public viewing of graphical RNA-seq results for coding and non-coding RNAs in young and old flies. Taken together, our results suggest that aging organisms recruit the circadian system to launch a temporally coordinated defense to cope with their increasingly stressful cellular environments. RNA-Seq was collected around the clock every 4 hours for young (5 day) and old (55 day) Drosophila melanogaster heads.