title: DAF-12-dependent rescue of dauer formation in Caenorhabditis elegans by (25S)-cholestenoic acid.
abstract: Population density, temperature and food availability all regulate the formation of the Caenorhabditis elegans dauer larva by modulating endocrine signaling pathways. The orphan nuclear receptor DAF-12 is pivotal for the decision to form a dauer or to undergo normal reproductive development. The DAF-12 ligand has been predicted to be a sterol that is metabolized by DAF-9, a cytochrome P450. Here we chemically characterize purified lipophilic nematode extracts and show that the ligand for DAF-12 contains a carboxyl moiety and is likely to be derived from a sterol. Using a candidate ligand approach we find that the C27 bile acid cholestenoic acid (5-cholesten-3beta-ol-(25S)-carboxylic acid) promotes reproductive growth in dauer-constitutive mutants in a daf-9- and daf-12-dependent manner. Furthermore, we find that cholestenoic acid can act as a DAF-12 ligand by activating DAF-12 in a cell-based transcription assay. Analysis of dauer-rescuing lipophilic extracts from nematodes by gas chromatography-mass spectrometry indicates the presence of several regioisomers of cholestenoic acid that are distinct from Delta(5)-cholestenoic acid and are not present in extracts from daf-9 mutants. These data suggest that carboxylated sterols may be key determinants of life history.
authors.affiliation: Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Held
authors.forename: Mark P
authors.initials: MP
authors.lastname: White
authors.forename: Alfred L
authors.initials: AL
authors.lastname: Fisher
authors.forename: Bradford W
authors.initials: BW
authors.lastname: Gibson
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Lithgow
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Gill
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002782:Cholestenes / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007814:Larva / Q000378:metabolism / Q000502:physiology*; D008024:Ligands; D009154:Mutation; D010641:Phenotype; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D029742:Caenorhabditis elegans Proteins; D002782:Cholestenes; C410905:DAF-12 protein, C elegans; D008024:Ligands; D018160:Receptors, Cytoplasmic and Nuclear; C514718:cholestenoic acid; D003577:Cytochrome P-450 Enzyme System; C486228:DAF-9 protein, C elegans