The gonad is well known to be important for reproduction but also affects animal life span. Removal of germ cells - the sperm and egg producing cells - increases longevity of the roundworm Caenorhabditis elegans. However, the underlying molecular mechanisms were a mystery. [The] roundworm Caenorhabditis elegans is a commonly used model organism in the field of ageing research. It develops from an egg to adult through four larval stages. These developmental stages are controlled by a developmental clock.
[Researchers] used a laser to remove the germ cells. They found that the remaining gonadal cells trigger production of a steroid hormone called dafachronic acid. Dafachronic acid activates so-called microRNAs, which work as tiny molecular switches causing changes in gene expression that promote longevity. Interestingly, this same steroid hormone-microRNA switch was previously shown [to] be part of the developmental clock. Thus, the loss of the germ cells ultimately causes the worm to use developmental timers to put in motion a life-prolonging programme.