title: Conservation of IGF2-H19 and IGF2R imprinting in sheep: effects of somatic cell nuclear transfer.
abstract: In different mammalian species, in vitro culture and manipulation can lead to aberrant fetal and peri-natal development. It has been postulated that these diverse abnormalities are caused by epigenetic alterations and that these could affect genes that are regulated by genomic imprinting. To explore this hypothesis relative to somatic cell nuclear transfer in sheep, we investigated whether the ovine H19-IGF2 and IGF2R loci are imprinted and analysed their DNA methylation status in cloned lambs. A comparison between parthenogenetic and control concepti established that imprinting at these two growth-related loci is evolutionarily conserved in sheep. As in humans and mice, IGF2R and H19 comprise differentially methylated regions (DMRs) that are methylated on one of the two parental alleles predominantly. In tongue tissue from 12 out of 13 cloned lambs analysed, the DMR in the second intron of IGF2R had strongly reduced levels of DNA methylation. The DMR located upstream of the ovine H19 gene was found to be similarly organised as in humans and mice, with multiple CTCF binding sites. At this DMR, however, aberrant methylation was observed in only one of the cloned lambs. Although the underlying mechanisms remain to be determined, our data indicate that somatic cell nuclear transfer procedures can lead to epigenetic deregulation at imprinted loci.
authors.affiliation: School of Human Development, University of Nottingham, Queens Medical Centre, Nottingham, UK.
authors.forename: Lorraine E
authors.initials: LE
authors.lastname: Young
authors.forename: Angelika E
authors.initials: AE
authors.lastname: Schnieke
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: McCreath
authors.forename: Sébastien
authors.initials: S
authors.lastname: Wieckowski
authors.forename: Galia
authors.initials: G
authors.lastname: Konfortova
authors.forename: Kenneth
authors.initials: K
authors.lastname: Fernandes
authors.forename: Grazyna
authors.initials: G
authors.lastname: Ptak
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Kind
authors.forename: Ian
authors.initials: I
authors.lastname: Wilmut
authors.forename: Pasqualino
authors.initials: P
authors.lastname: Loi
authors.forename: Robert
authors.initials: R
authors.lastname: Feil
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics* / Q000502:physiology*; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008297:Male; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics*; D017527:Receptor, IGF Type 2 / Q000235:genetics*; D012756:Sheep / Q000235:genetics*; D014059:Tongue
chemical_list: C094335:H19 long non-coding RNA; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017527:Receptor, IGF Type 2; D007335:Insulin-Like Growth Factor II