The C. elegans developmental timing protein LIN-42 regulates diapause in response to environmental cues.
Environmental conditions can have a major impact on developmental progression in animals. For example, when C. elegans larvae encounter harsh conditions they can reversibly halt the passage of developmental time by forming a long-lived dauer larva at the end of the second larval stage. Here, we show that the period ... homolog lin-42, known to control developmental time, also acts as a component of a switch that mediates dauer entry. Loss of lin-42 function renders animals hypersensitive to dauer formation under stressful conditions, whereas misexpression of lin-42 in the pre-dauer stage inhibits dauer formation, indicating that lin-42 acts as a negative regulator of this life history decision. These phenotypes place LIN-42 in opposition to the ligand-free form of the nuclear receptor DAF-12, which indirectly senses environmental conditions and helps to integrate external cues into developmental decisions. Mutations that impair DAF-12 ligand binding are exquisitely sensitive to the absence of lin-42, whereas overexpression of LIN-42 can suppress the dauer constitutive phenotype of a ligand-insensitive daf-12 mutant, suggesting that LIN-42 and DAF-12 are intimate partners in controlling the decision to become a dauer larva. The functional outputs of Period family proteins and nuclear receptors also converge in other organisms, suggesting that the relationship between lin-42 and daf-12 represents an ancient genetic framework for responding to environmental stimuli.
Mesh Terms:
Adaptation, Physiological, Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Cues, DNA Primers, Environment, Life Cycle Stages, Period Circadian Proteins, Receptors, Cytoplasmic and Nuclear, Reverse Transcriptase Polymerase Chain Reaction, Transcription Factors, Two-Hybrid System Techniques
Adaptation, Physiological, Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Cues, DNA Primers, Environment, Life Cycle Stages, Period Circadian Proteins, Receptors, Cytoplasmic and Nuclear, Reverse Transcriptase Polymerase Chain Reaction, Transcription Factors, Two-Hybrid System Techniques
Development
Date: Oct. 01, 2010
PubMed ID: 20843862
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