title: In vitro fertilization causes epigenetic modifications to the onset of gene expression from the zygotic genome in mice.
abstract: The effect of in vitro fertilization (IVF) and culture of mouse preimplantation embryos in vitro on the onset of expression of insulin-like growth factor 1 (IGF-1) ligand and receptor, insulin ligand and receptor, alpha-transforming growth factor (alpha-TGF) ligand, PAF:acetylhydrolase 1b (Pafah1b; alpha(1), alpha(2), and beta subunits of the enzyme), and the transcription requiring complex proteins (TRC) was examined. The IGF-1 ligand was detected in preimplantation embryos by immunofluorescence at all developmental stages tested. However, IVF and culture significantly reduced the amount of protein detected in the 8-cell embryo and blastocyst (P: < 0.001), and this was due to a delayed onset of expression of the mRNA for IGF-1 ligand from the zygotic genome. The expression of the alpha(1) subunit of Pafah1b was first detected at the 2-cell stage in fresh embryos, but expression was significantly retarded (P: < 0.001) when IVF and ISF (in situ-fertilized) zygotes were cultured in vitro. In vitro fertilization or ISF did not delay the onset of expression of TRC nor mRNA for the IGF-1 receptor, insulin receptor, alpha(2) or beta subunit of Pafah1b, nor did they effect alpha-TGF protein synthesis. Thus, IVF causes epigenetic modification in the normal pattern of expression of some but not all genes involved in normal embryo growth and survival.
authors.affiliation: Human Reproduction Unit, Department of Physiology, University of Sydney, Royal North Shore Hospital of Sydney, St. Leonards, NSW 2065, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Stojanov
authors.forename: C
authors.initials: C
authors.lastname: O'Neill
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000818:Animals; D003470:Culture Media; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000235:genetics* / Q000502:physiology*; D016678:Genome; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010741:Phospholipases A / Q000096:biosynthesis; D010972:Platelet Activating Factor / Q000378:metabolism; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D011972:Receptor, Insulin / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013094:Spermatozoa / Q000502:physiology; D015053:Zygote / Q000502:physiology*
chemical_list: D003470:Culture Media; D010972:Platelet Activating Factor; D012333:RNA, Messenger; D011972:Receptor, Insulin; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase