title: DNA methylation in the IGF2 intragenic DMR is re-established in a sex-specific manner in bovine blastocysts after somatic cloning.
abstract: The recent identification of an intragenic differentially methylated region (DMR) within the last exon of the bovine Insulin-like growth factor 2 (IGF2) gene provides a diagnostic tool for in-depth investigation of bovine imprinting and regulatory mechanisms which are active during embryo development. Here, we used bisulfite sequencing to compare sex-specific DNA methylation patterns within this DMR in bovine blastocysts produced in vivo, by in vitro fertilization and culture, SCNT, androgenesis or parthenogenesis. In in vivo derived embryos, DNA methylation was removed from this intragenic DMR after fertilization, but partially replaced by the time the embryo reached the blastocyst stage. Among embryos developing in vivo, the level of DNA methylation was significantly lower in female than in male blastocysts. This sexual dimorphism was also found between parthenogenetic and androgenetic embryos, and followed the donor cell sex in SCNT derived blastocysts and is evidence for correct methylation reprogramming in SCNT embryos.
authors.affiliation: Institute of Farm Animal Genetics (FLI), Hoeltystrasse 10, D-31535 Neustadt-Mariensee, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Gebert
authors.forename: Christine
authors.initials: C
authors.lastname: Wrenzycki
authors.forename: Doris
authors.initials: D
authors.lastname: Herrmann
authors.forename: Daniela
authors.initials: D
authors.lastname: Gröger
authors.forename: Janina
authors.initials: J
authors.lastname: Thiel
authors.forename: Richard
authors.initials: R
authors.lastname: Reinhardt
authors.forename: Hans
authors.initials: H
authors.lastname: Lehrach
authors.forename: Petra
authors.initials: P
authors.lastname: Hajkova
authors.forename: Andrea
authors.initials: A
authors.lastname: Lucas-Hahn
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Carnwath
authors.forename: Heiner
authors.initials: H
authors.lastname: Niemann