(A) Under favorable conditions, insulin/IGF and TGF-β signaling drive biosynthesis of steroidal DAF-12-ligands. Liganded DAF-12 promotes development, in part via transcription of the let-7-family microRNA’s mir-84 and mir-241. Under unfavorable conditions, ligand biosynthesis is inhibited, resulting in interaction of unliganded DAF-12 with its co-repressor DIN-1.
(B) Previously described DAF-12-ligands and proposed biosynthetic pathways. DAF-12-ligand biosynthesis is downregulated in response to dauer pheromone, a blend of ascarosides, e.g. the shown ascr#2 (red).