title: Environmental Canalization of Life Span and Gene Expression in Caenorhabditis elegans.
abstract: Animals, particularly poikilotherms, exhibit distinct physiologies at different environmental temperatures. Here, we hypothesized that temperature-based differences in physiology could affect the amount of variation in complex quantitative traits. Specifically, we examined, in Caenorhabditis elegans, how different temperatures (15°C, 20°C, and 25°C) affected the amount of interindividual variation in life span and also expression of three reporter genes-transcriptional reporters for vit-2, gpd-2, and hsp-16.2 (a life-span biomarker). We found the expected inverse relationship between temperature and average life span. Surprisingly, we found that at the highest temperature, there were fewer differences between individuals in life span and less interindividual variation in expression of all three reporters. We suggest that growth at 25°C might canalize (reduce interindividual differences in) life span and expression of some genes by eliciting a small constitutive heat shock response. Growth at 25°C requires wild-type hsf-1, which encodes the main heat shock response transcriptional activator. We speculate that increased chaperone activity at 25°C may reduce interindividual variation in gene expression by increasing protein folding efficiency. We hypothesize that reduced variation in gene expression may ultimately cause reduced variation in life span.
authors.affiliation: Department of Pathology, University of Washington, Seattle.
authors.forename: Alexander
authors.initials: A
authors.lastname: Mendenhall
authors.affiliation: Department of Pathology, University of Washington, Seattle.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Crane
authors.affiliation: Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor.
authors.forename: Scott
authors.initials: S
authors.lastname: Leiser
authors.affiliation: Department of Pathology, University of Washington, Seattle.
authors.forename: George
authors.initials: G
authors.lastname: Sutphin
authors.affiliation: Institute for Behavioral Genetics.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Tedesco
authors.affiliation: Department of Pathology, University of Washington, Seattle.
authors.forename: Matt
authors.initials: M
authors.lastname: Kaeberlein
authors.affiliation: Institute for Behavioral Genetics.|Department of Integrative Physiology.|Biofrontiers Institute, University of Colorado, Boulder.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Johnson
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington.
authors.forename: Roger
authors.initials: R
authors.lastname: Brent
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D004777:Environment; D015870:Gene Expression / Q000502:physiology*; D059647:Gene-Environment Interaction; D017930:Genes, Reporter / Q000502:physiology*; D005819:Genetic Markers / Q000502:physiology; D008136:Longevity / Q000235:genetics; D018832:Molecular Chaperones / Q000502:physiology*; D013696:Temperature; D000071436:Thermotolerance / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; D005819:Genetic Markers; D018832:Molecular Chaperones; D014157:Transcription Factors; C474710:heat shock factor-1, C elegans
keywords: Aging; Biomarker; Nongenetic; Proteostasis; Variation