title: Long-range chromatin interactions at the mouse Igf2/H19 locus reveal a novel paternally expressed long non-coding RNA.
abstract: Parental genomic imprinting at the Igf2/H19 locus is controlled by a methylation-sensitive CTCF insulator that prevents the access of downstream enhancers to the Igf2 gene on the maternal chromosome. However, on the paternal chromosome, it remains unclear whether long-range interactions with the enhancers are restricted to the Igf2 promoters or whether they encompass the entire gene body. Here, using the quantitative chromosome conformation capture assay, we show that, in the mouse liver, the endodermal enhancers have low contact frequencies with the Igf2 promoters but display, on the paternal chromosome, strong interactions with the intragenic differentially methylated regions 1 and 2. Interestingly, we found that enhancers also interact with a so-far poorly characterized intergenic region of the locus that produces a novel imprinted long non-coding transcript that we named the paternally expressed Igf2/H19 intergenic transcript (PIHit) RNA. PIHit is expressed exclusively from the paternal chromosome, contains a novel discrete differentially methylated region in a highly conserved sequence and, surprisingly, does not require an intact ICR/H19 gene region for its imprinting. Altogether, our data reveal a novel imprinted domain in the Igf2/H19 locus and lead us to propose a model for chromatin folding of this locus on the paternal chromosome.
authors.affiliation: Institut de Génétique Moléculaire de Montpellier, UMR5535 CNRS Universités Montpellier I et Montpellier II, 1919 Route de Mende, 34293 Montpellier cedex 5, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Court
authors.forename: Marion
authors.initials: M
authors.lastname: Baniol
authors.forename: Hélène
authors.initials: H
authors.lastname: Hagege
authors.forename: Julie Sandrine
authors.initials: JS
authors.lastname: Petit
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Lelay-Taha
authors.forename: Françoise
authors.initials: F
authors.lastname: Carbonell
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Guy
authors.initials: G
authors.lastname: Cathala
authors.forename: Thierry
authors.initials: T
authors.lastname: Forne
mesh_terms: D000818:Animals; D002843:Chromatin / Q000737:chemistry*; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D021901:DNA, Intergenic / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D056426:Genetic Loci; D018392:Genomic Imprinting; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D051379:Mice; D008957:Models, Genetic; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics* / Q000378:metabolism
chemical_list: D002843:Chromatin; D021901:DNA, Intergenic; C094335:H19 long non-coding RNA; C513121:IGF2 protein, mouse; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II