Combined informatic and expression screen identifies the novel DAF-16 target HLH-13

Insulin/IGF-signaling (IIS) affects longevity, stress resistance and metabolism in worms, flies, and mammals. The Forkhead transcription factor DAF-16/FOXO is the major downstream effector of IIS and is responsible for the activation and repression of genes that mediate the diverse effects of IIS. We surveyed a set of informatically predicted conserved DAF-16/FOXO target genes and identified the novel DAF-16 direct target hlh-13. hlh-13 is the predicted homolog of the mammalian transcription factor Ptf1a, a critical determinant of pancreatic development. We found that an hlh-13 mutant exits L1 arrest and IIS-dependent dauer diapause faster than control worms, but is not involved in lifespan or resistance to a variety of stresses. Our results have identified a novel DAF-16 target gene and linked its function to known outputs of IIS. Considering the high conservation of IIS in diverse species, our results also hint at an intriguing connection of IIS and Ptf1a in mammals.