title: Reduction of gene repair by selenomethionine with the use of single-stranded oligonucleotides.
abstract: BACKGROUND
  The repair of single base mutations in mammalian genes can be directed by single-stranded oligonucleotides in a process known as targeted gene repair. The mechanism of this reaction is currently being elucidated but likely involves a pairing step in which the oligonucleotide align in homologous register with its target sequence and a correction step in which the mutant base is replaced by endogenous repair pathways. This process is regulated by the activity of various factors and proteins that either elevate or depress the frequency at which gene repair takes place.
  
  
  RESULTS
  In this report, we find that addition of selenomethionine reduces gene repair frequency in a dose-dependent fashion. A correlation between gene repair and altered cell cycle progression is observed. We also find that selenium induces expression of Ref-1 which, in turn, modifies the activity of p53 during the cell cycle.
  
  
  CONCLUSIONS
  We can conclude from the results that the suppression of gene repair by introduction of selenomethionine occurs through a p53-associated pathway. This result indicates that the successful application of gene repair for treatment of inherited disorders may be hampered by indirect activation of endogenous suppressor functions.
authors.affiliation: Department of Biological Sciences, University of Delaware, Delaware Biotechnology Institute, 15 Innovation Way Newark, DE 19711, USA. tischwar@udel.edu <tischwar@udel.edu>
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Schwartz
authors.forename: Eric B
authors.initials: EB
authors.lastname: Kmiec
mesh_terms: D001483:Base Sequence; D002453:Cell Cycle; D045744:Cell Line, Tumor; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000235:genetics*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics*; D012643:Selenium / Q000494:pharmacology; D012645:Selenomethionine / Q000494:pharmacology* / Q000633:toxicity; D052416:Targeted Gene Repair; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D009841:Oligonucleotides; D016159:Tumor Suppressor Protein p53; D049452:Green Fluorescent Proteins; D012645:Selenomethionine; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D012643:Selenium