title: The HIF-1 hypoxia-inducible factor modulates lifespan in C. elegans.
abstract: During normal development or during disease, animal cells experience hypoxic (low oxygen) conditions, and the hypoxia-inducible factor (HIF) transcription factors implement most of the critical changes in gene expression that enable animals to adapt to this stress. Here, we examine the roles of HIF-1 in post-mitotic aging. We examined the effects of HIF-1 over-expression and of hif-1 loss-of-function mutations on longevity in C. elegans, a powerful genetic system in which adult somatic cells are post-mitotic. We constructed transgenic lines that expressed varying levels of HIF-1 protein and discovered a positive correlation between HIF-1 expression levels and lifespan. The data further showed that HIF-1 acted in parallel to the SKN-1/NRF and DAF-16/FOXO transcription factors to promote longevity. HIF-1 over-expression also conferred increased resistance to heat and oxidative stress. We isolated and characterized additional hif-1 mutations, and we found that each of 3 loss-of-function mutations conferred increased longevity in normal lab culture conditions, but, unlike HIF-1 over-expression, a hif-1 deletion mutation did not extend the lifespan of daf-16 or skn-1 mutants. We conclude that HIF-1 over-expression and hif-1 loss-of-function mutations promote longevity by different pathways. These data establish HIF-1 as one of the key stress-responsive transcription factors that modulate longevity in C. elegans and advance our understanding of the regulatory networks that link oxygen homeostasis and aging.
authors.affiliation: Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Shao
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhai
authors.forename: Chuan
authors.initials: C
authors.lastname: Shen
authors.forename: Jo Anne
authors.initials: JA
authors.lastname: Powell-Coffman
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D008136:Longevity; D009154:Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D029742:Caenorhabditis elegans Proteins; C541178:HIF-1 protein, C elegans; D014157:Transcription Factors