title: A T/C polymorphism in the GPX4 3'UTR affects the selenoprotein expression pattern and cell viability in transfected Caco-2 cells.
abstract: BACKGROUND
  Synthesis of selenoproteins such as glutathione peroxidases (GPx) requires a specific tRNA and a stem-loop structure in the 3'untranslated region (3'UTR) of the mRNA. A common single nucleotide polymorphism occurs in the GPX4 gene in a region corresponding to the 3'UTR.
  
  
  METHODS
  The two variant 3'UTR sequences were linked to sequences from a selenoprotein reporter gene (iodothyronine deiodinase) and expressed in Caco-2 cells. Clones expressing comparable levels of deiodinase (assessed by real-time PCR) were selected and their response to tert-butyl hydroperoxide assessed by cell viability and measurement of reactive oxygen species. Selenoprotein expression was assessed by real-time PCR, enzyme activity and immunoassay.
  
  
  RESULTS
  When selenium supply was low, cells overexpressing the C variant 3'UTR showed lower viability after oxidative challenge, increased levels of reactive oxygen species and lower GPx activity and SelH mRNA expression compared to cells overexpressing the T variant. After selenium supplementation, cell viability and GPx4 expression were higher in the cells overexpressing the C variant. Expression of transgenes incorporating the T/C variant GPX4 (rs713041) sequences in Caco-2 cells leads to alterations in both cell viability after an oxidative challenge and selenoprotein expression. This suggests that the two variants compete differently in the selenoprotein hierarchy.
  
  
  CONCLUSIONS
  The data provide evidence that the T/C variant GPX4 (rs713041) alters the pattern of selenoprotein synthesis if selenium intake is low. Further work is required to assess the impact on disease susceptibility.
authors: Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
authors: Hannah
authors: H
authors: Gautrey
authors: Fergus
authors: F
authors: Nicol
authors: Alan A
authors: AA
authors: Sneddon
authors: Judith
authors: J
authors: Hall
authors: John
authors: J
authors: Hesketh
mesh_terms: D020413:3' Untranslated Regions; D018938:Caco-2 Cells; D002470:Cell Survival; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics*; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D011110:Polymorphism, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012643:Selenium / Q000494:pharmacology; D051140:Selenoproteins / Q000235:genetics / Q000378:metabolism*; D014131:Trace Elements / Q000494:pharmacology; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; D051140:Selenoproteins; D014131:Trace Elements; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase; D012643:Selenium