Although the role of the C. elegans FoxO transcription factor DAF-16 in promoting longevity is well established, how DAF-16/FoxO extends life span remains poorly understood. While the identities of thousands of DAF-16/FoxO target genes are known, mechanistic links between DAF-16/FoxO-dependent regulation of specific genes and DAF-16/FoxO-dependent life span extension are lacking. We have discovered that a conserved cholinesterase family member encoded by the DAF-16/FoxO target gene
cest-1.1 is required for full life span extension in the context of reduced DAF-2 insulin-like signaling and sufficient to extend life span when expressed in a wild-type background. A functional CEST-1.1::GFP fusion protein is expressed specifically in the intestine and localizes to the apical plasma membrane. Comparative metabolomic analysis using HPLC-high resolution mass spectrometry revealed that CEST-1.1 is required for the biosynthesis of two structurally novel nucleoside-like ascarosides termed uglas#1 and uglas#11. These surprising findings support a role for an unprecedented class of metabolites in life span control and orthogonally expand the landscape of biogenic small molecules that may influence aging.