title: Regulation of Caenorhabditis elegans vitellogenesis by DAF-2/IIS through separable transcriptional and posttranscriptional mechanisms.
abstract: BACKGROUND
  Evolutionary theories of aging propose that longevity evolves as a competition between reproduction and somatic maintenance for a finite pool of resources. Reproduction is thought to shorten lifespan by depleting resources from processes promoting somatic maintenance. Maternal yolk production, vitellogenesis, represents a significant maternal cost for reproduction and is suppressed under genetic and environmental conditions that extend lifespan. However, little is known about the pathways regulating vitellogenesis in response to prolongevity cues.
  
  
  RESULTS
  In order to identify mechanisms that suppress vitellogenesis under prolongevity conditions, we studied factors regulating vitellogenesis in C. elegans nematodes. In C. elegans, vitellogenesis is depressed in the absence of insulin-like signaling (IIS). We found that the C. elegans daf-2/IIS pathway regulates vitellogenesis through two mechanisms. vit-2 transcript levels in daf-2 mutants were indirectly regulated through a germline-dependent signal, and could be rescued by introduction of daf-2(+) sperm. However, yolk protein (YP) levels in daf-2 mutants were also regulated by germline-independent posttranscriptional mechanisms.
  
  
  CONCLUSIONS
  C. elegans vitellogenesis is regulated transcriptionally and posttranscriptionally in response to environmental and reproductive cues. The daf-2 pathway suppressed vitellogenesis through transcriptional mechanisms reflecting reproductive phenotypes, as well as distinct posttranscriptional mechanisms. This study reveals that pleiotropic effects of IIS pathway mutations can converge on a common downstream target, vitellogenesis, as a mechanism to modulate longevity.
authors.affiliation: Laboratory of Neurosciences, NIA Intramural Research Program, NIH, Baltimore, MD 21224, USA.
authors.forename: Ana S
authors.initials: AS
authors.lastname: DePina
authors.forename: Wendy B
authors.initials: WB
authors.lastname: Iser
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Park
authors.forename: Stuart
authors.initials: S
authors.lastname: Maudsley
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wilson
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Wolkow
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D058685:Genetic Pleiotropy / Q000502:physiology; D008136:Longevity / Q000235:genetics / Q000502:physiology; D008297:Male; D009154:Mutation; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013094:Spermatozoa / Q000378:metabolism; D014158:Transcription, Genetic; D014818:Vitellogenesis / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; C107483:DAF-2 protein, C elegans; D011972:Receptor, Insulin