Flies lacking the FOXO gene, a homolog of the worm gene daf-16, whose activity is essential for lifespan extension in insulin-life growth factor signaling mutants, have perturbed circadian rhythms (Zheng et al.). Specifically, when subjected to oxidative stress, these flies lose behavioral rhythms that are specified by the central circadian “clock.” Furthermore, the FOXO mutants, which are known to have decreased lifespans and an accelerated aging phenotype, suffer from increasingly disrupted rhythms as they age:
…foxo mutants showed a rapid decline in rest:activity rhythms with age, supporting the idea that the increase of oxidative stress contributes to age-associated degeneration of behavioral rhythms and indicating the importance of FOXO in mitigating this deterioration.
While it’s by no means clear that the same mechanisms are at play, this is reminiscent of the dysregulation of circadian behaviors in elderly humans, who often report significant changes in their sleep cycles. Could aging cause similar circadian disruption in humans?