title: Embryonic imprinting perturbations do not originate from superovulation-induced defects in DNA methylation acquisition.
abstract: OBJECTIVE
  To investigate whether superovulation disrupts maternal imprint acquisition in oocytes.
  
  
  METHODS
  Animal model.
  
  
  METHODS
  Academic institute.
  
  
  METHODS
  Spontaneously ovulated and superovulated mice.
  
  
  METHODS
  Low and high hormone dosage treatments were administered to females, and ovulated metaphase II oocytes were collected.
  
  
  METHODS
  Imprinted DNA methylation was analyzed at Snrpn, Kcnq1ot1, Peg3, and H19 in individual oocytes.
  
  
  RESULTS
  Examination of 125 individual oocytes derived from females subjected to low and high hormone treatments revealed normal imprinted methylation patterns that were comparable to oocytes derived from spontaneously ovulated females.
  
  
  CONCLUSIONS
  Maternal imprint acquisition was not affected by superovulation. Given its aberrant effects during preimplantation development, superovulation must instead disrupt maternal-effect gene products that are required after fertilization for imprint maintenance. These results eliminate imprint acquisition per se as the initial stage of imprint loss and point to the importance of analyses on early embryos after procedures involving oocyte manipulation.
authors.affiliation: Departments of Obstetrics and Gynecology and Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Denomme
authors.forename: Liyue
authors.initials: L
authors.lastname: Zhang
authors.forename: Mellissa R W
authors.initials: MR
authors.lastname: Mann
mesh_terms: D000818:Animals; D019175:DNA Methylation / Q000235:genetics*; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D018392:Genomic Imprinting / Q000235:genetics*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000235:genetics; D009865:Oocytes / Q000502:physiology*; D010060:Ovulation / Q000235:genetics; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics; D027724:Reproductive Techniques, Assisted; D013480:Superovulation / Q000235:genetics*
chemical_list: C094335:H19 long non-coding RNA; C449939:KCNQ1OT1 RNA; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; C097901:Peg3 protein, mouse; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; C486713:SNURF protein, mouse