Signals from the reproductive system regulate the lifespan of C-elegans

Understanding hew the ageing process is regulated is a fascinating and fund amental problem in biology. Here we demonstrate that signals from the repro ductive system influence the Lifespan of the nematode Cacnorhabditis elegan s. If the cells that give rise to the germ line are killed with a laser mic robeam, the lifespan of the animal is extended. Our findings suggest that g ermline signals act by modulating the activity of an insulin/IGF-1 (insulin -like growth factor) pathway that is known to regulate the ageing of this o rganism. Mutants with reduced activity of the insulin/IGF-1-receptor homolo gue DAF-2 have been shown to live twice as long as normal(1-3), and their l ongevity requires the activity of DAF-16, a member of the forkhead/winged-h elix family of transcriptional regulators(1,2,4,5). We find that, in order for germline ablation to extend lifespan, DAF-16 is required, as well as a putative nuclear hormone receptor, DAF-12 (refs 6, 7). In addition, our fin dings suggest that signals from the somatic gonad also influence ageing, an d that this effect requires DAF-2 activity. Together, our findings imply th at the C. elegans insulin/IGF-1 system integrates multiple signals to defin e the animal's rate of ageing. This study demonstrates an inherent relation ship between the reproductive state of this animal and its lifespan, and ma y have implications for the co-evolution of reproductive capability and lon gevity.