A soma-to-germline transformation in long-lived C. elegans mutants

Unlike the soma which ages during the lifespan of multicellular organisms, the germline traces an essentially immortal lineage. Genomic instability in somatic cells increases with age, and this decline in somatic maintenance might be regulated to facilitate resource reallocation toward reproduction at the expense of cellular senescence. We report here that C. elegans mutants with increased longevity exhibit a soma-to-germline transformation of gene expression programs normally limited to the germline. Decreased insulin-like signaling causes the somatic misexpression of germline-limited pie-1 and pgl family of genes in intestinal and ectodermal tissues. DAF-16/FoxO, the major transcriptional effector of insulin-like signaling, regulates pie-1 expression by directly binding to the pie-1 promoter. The somatic tissues of insulin-like mutants are more germline-like and protected from genotoxic stress. Gene inactivation of components of the cytosolic chaperonin complex that induce increased longevity also cause somatic misexpression of PGL-1. These results suggest that the acquisition of germline characteristics by the somatic cells of C. elegans mutants with increased longevity contributes to their increased health and survival.