RRC ID 46340
Author Savory FR, Sait SM, Hope IA.
Title DAF-16 and Δ9 desaturase genes promote cold tolerance in long-lived Caenorhabditis elegans age-1 mutants.
Journal PLoS One
Abstract In Caenorhabditis elegans, mutants of the conserved insulin/IGF-1 signalling (IIS) pathway are long-lived and stress resistant due to the altered expression of DAF-16 target genes such as those involved in cellular defence and metabolism. The three Δ(9) desaturase genes, fat-5, fat-6 and fat-7, are included amongst these DAF-16 targets, and it is well established that Δ(9) desaturase enzymes play an important role in survival at low temperatures. However, no assessment of cold tolerance has previously been reported for IIS mutants. We demonstrate that long-lived age-1(hx546) mutants are remarkably resilient to low temperature stress relative to wild type worms, and that this is dependent upon daf-16. We also show that cold tolerance following direct transfer to low temperatures is increased in wild type worms during the facultative, daf-16 dependent, dauer stage. Although the cold tolerant phenotype of age-1(hx546) mutants is predominantly due to the Δ(9) desaturase genes, additional transcriptional targets of DAF-16 are also involved. Surprisingly, survival of wild type adults following a rapid temperature decline is not dependent upon functional daf-16, and cellular distributions of a DAF-16::GFP fusion protein indicate that DAF-16 is not activated during low temperature stress. This suggests that cold-induced physiological defences are not specifically regulated by the IIS pathway and DAF-16, but expression of DAF-16 target genes in IIS mutants and dauers is sufficient to promote cross tolerance to low temperatures in addition to other forms of stress.
Volume 6(9)
Pages e24550
Published 2011-1-1
DOI 10.1371/journal.pone.0024550
PII PONE-D-11-11397
PMID 21931751
PMC PMC3169625
MeSH Acclimatization Animals Caenorhabditis elegans / genetics* Caenorhabditis elegans Proteins / genetics* Caenorhabditis elegans Proteins / physiology* Cold Temperature Forkhead Transcription Factors Green Fluorescent Proteins / metabolism Insulin / metabolism Insulin-Like Growth Factor I / metabolism* Mutation Phosphatidylinositol 3-Kinases / genetics Phosphatidylinositol 3-Kinases / physiology* RNA Interference Signal Transduction Stearoyl-CoA Desaturase / genetics* Temperature Time Factors Transcription Factors / genetics*
IF 2.74
Times Cited 25
C.elegans tm331 tm420