A Conserved Endocrine Mechanism Controls the Formation of Dauer and Infective Larvae in Nematodes

Under harsh environmental conditions, Caenorhabditis elegans larvae undergo arrest and form dauer larvae that can attach to other animals to facilitate dispersal [1]. It has been argued that this phenomenon, called phoresy, represents an intermediate step toward parasitism [2, 3]. Indeed, parasitic...

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Bibliographic Details
Published in:Current biology 2009-01, Vol.19 (1), p.67-71
Main Authors: Ogawa, Akira, Streit, Adrian, Antebi, Adam, Sommer, Ralf J.
Format: Article
Language:English
Subjects:
Animals
Biological Evolution
Caenorhabditis elegans - physiology
Caenorhabditis elegans Proteins - genetics
Caenorhabditis elegans Proteins - metabolism
Cholestenes - metabolism
Cholestenes - pharmacology
Conserved Sequence - genetics
EVOL_ECOL
Larva - drug effects
Larva - physiology
Life Cycle Stages - drug effects
Phenotype
Phylogeny
Receptors, Cytoplasmic and Nuclear - genetics
Receptors, Cytoplasmic and Nuclear - metabolism
Reverse Transcriptase Polymerase Chain Reaction
Species Specificity
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Summary:Under harsh environmental conditions, Caenorhabditis elegans larvae undergo arrest and form dauer larvae that can attach to other animals to facilitate dispersal [1]. It has been argued that this phenomenon, called phoresy, represents an intermediate step toward parasitism [2, 3]. Indeed, parasitic nematodes invade their hosts as infective larvae, a stage that shows striking morphological similarities to dauer larvae [1]. Although the molecular regulation of dauer entry in C. elegans involves insulin and TGF-β signaling [4–8], studies of TGF-β orthologs in parasitic nematodes didn't provide evidence for a common origin of dauer and infective larvae [9–14]. To identify conserved regulators between Caenorhabditis and parasitic nematodes, we used an evolutionary approach involving Pristionchus pacificus as an intermediate. We show by mutational and pharmacological analysis that Pristionchus and Caenorhabditis share the dafachronic acid-DAF-12 system as the core endocrine module for dauer formation. One dafachronic acid, Δ7-DA, has a conserved role in the mammalian parasite Strongyloides papillosus by controlling entry into the infective stage. Application of Δ7-DA blocks formation of infective larvae and results in free-living animals. Conservation of this small molecule ligand represents a fundamental link between dauer and infective larvae and might provide a general strategy for nematode parasitism.
ISSN:0960-9822
1879-0445
DOI:10.1016/j.cub.2008.11.063