title: High oxygen tension increases global methylation in bovine 4-cell embryos and blastocysts but does not affect general retrotransposon expression.
abstract: Retrotransposons are transposable elements that insert extra copies of themselves throughout the genome via an RNA intermediate using a 'copy and paste' mechanism. They account for more than 44% of the bovine genome and have been reported to be functional, especially during preimplantation embryo development. In the present study, we tested whether high oxygen tension (20% O2) influences global DNA methylation analysed by immunofluorescence staining of developing bovine embryos and whether this has an effect on the expression of some selected retrotransposon families. High oxygen tension significantly increased global DNA methylation in 4-cell embryos and blastocysts. A significant expression difference was observed for ERV1-1-I_BT in female blastocysts, but no significant changes were observed for the other retrotransposon families tested. Therefore, the study indicates that global DNA methylation is not necessarily correlated with retrotransposon expression in bovine preimplantation embryos.
authors.affiliation: Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium.
authors.forename: Karen
authors.initials: K
authors.lastname: Goossens
authors.affiliation: Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium.
authors.forename: Mario
authors.initials: M
authors.lastname: Van Poucke
authors.affiliation: Laboratory of General Biochemistry and Physical Pharmacy,Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Forier
authors.affiliation: Laboratory of General Biochemistry and Physical Pharmacy,Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: Kevin
authors.initials: K
authors.lastname: Braeckmans
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Van Soom
authors.affiliation: Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium.
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Peelman
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle; D019175:DNA Methylation; D047108:Embryonic Development; D005260:Female; D010100:Oxygen / Q000502:physiology*; D011247:Pregnancy; D018626:Retroelements
chemical_list: D018626:Retroelements; D010100:Oxygen