title: Differential methylation of pluripotency gene promoters in in vitro matured and vitrified, in vivo-matured mouse oocytes.
abstract: OBJECTIVE
  To assess the methylation patterns of four pluripotency gene promoters in mouse oocytes after in vivo maturation, in vitro maturation (IVM), and vitrification followed by IVM.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Three populations of metaphase II mouse oocytes were analyzed after in vivo maturation, IVM, and vitrification followed by IVM (V-IVM). Cumulus cells and blastocyst embryos were controls.
  
  
  METHODS
  The CpG methylation patterns (overall and CpG specific) in the promoters of four pluripotency genes (Oct4, Nanog, Foxd3, and Sox2) were analyzed for each cell type by traditional DNA bisulfite sequencing.
  
  
  METHODS
  Differences for overall methylation were evaluated using the Student's t-test and for individual CpG sites by χ2 analysis.
  
  
  RESULTS
  Significantly lower levels of overall methylation in promoters of Oct4 (25%) and Sox2 (4.5%) were noted in V-IVM oocytes compared with in vivo-matured oocytes (62.5% and 8.5%, respectively). Cumulus cell promoters were generally hypomethylated at Nanog, Foxd3. and Sox2, but hypermethylated at Oct4.
  
  
  CONCLUSIONS
  The methylation status of Oct4 and Sox2 promoters of V-IVM mouse oocytes are altered when compared with in vivo-matured oocytes. The biological risk and significance of these changes are unknown and this study indicates caution and that further analyses are warranted.
authors: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, School of Medicine, University of Utah, Salt Lake City, Utah 84108, USA.
authors: Colleen
authors: C
authors: Milroy
authors: Lihua
authors: L
authors: Liu
authors: Sue
authors: S
authors: Hammoud
authors: Ahmad
authors: A
authors: Hammoud
authors: C Matthew
authors: CM
authors: Peterson
authors: Douglas T
authors: DT
authors: Carrell
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D019175:DNA Methylation / Q000502:physiology; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism*; D009866:Oogenesis / Q000235:genetics* / Q000502:physiology; D039904:Pluripotent Stem Cells / Q000378:metabolism; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D058989:Vitrification
chemical_list: D051858:Forkhead Transcription Factors; C101757:Foxd3 protein, mouse; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; D012097:Repressor Proteins; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse