Visit our Expo - Redox and Inflammation signaling 2012

A new antisense transcript is involved in the genomic imprinting control at the
H19/IGF2 locus
Nathalie Berteaux 1 , Nicole Aptel 2 , Thierry Dugimont 1 , Guy Cathala 2 , Céline Janton 1 ,
Jean Coll 3 , Hubert Hondermarck 1 , Jean-Jacques Curgy 1 , Thierry Forné 2 and Eric
Adriaenssens 1 .
1 ERI-8 INSERM, UPRES-EA 1033, IFR 118, USTL, 59655 Villeneuve d’Ascq cedex,
France ; 2 Institut de Génétique Moléculaire, UMR 5535 CNRS, Université Montpellier
II, IFR 122, Montpellier, France ; 3 UMR 8527 CNRS, IBL, Institut Pasteur, Lille,
France.
E-mail : eric.adriaenssens@univ-lille1.fr
Natural antisense transcripts have been implicated in many aspects of eucaroytic gene
expression including genomic imprinting and RNA interference. Our group has identified a
new antisense transcript at the human and mouse H19/IGF2 locus, that we called 91H. This
locus belongs to an imprinting domain located in human chromosome 11p15.5 (homologue to
the mouse distal chromosome 7). H19 is expressed from the maternal allele and Igf-2 is
paternally expressed. Both genes share common regulatory sequences including the H19 5’
differentially methylated domain ICR (Imprinting Control Region) and the 3’ downstream
enhancer sequences.
In human, 91H is an 120 kb-long transcript, antisense to H19, spanning the entire H19
transcribed region and extending 69Kb and 39 kb downstream and upstream, respectively.
This includes the ICR and the 3’ enhancer regions but not the IGF2 transcription unit. The
promoter region is contained in the first intron of the MrpL23 gene (the H19 3’neighbouring
gene). In addition, we show that in mouse 91H is a biallelic transcript.
We demonstrate that this antisense RNA is a nuclear and short-lived transcipt in human and
mouse normal cells, but we observe its stabilization and accumulation in human breast
epithelial cells. Consistently, an in vivo study confirms these data revealing a 91H
overexpression in breast cancer biopsies. Furthermore, the developmental expression of 91H
is very similar to those of the H19 RNA.
Knock-down of 91H by RNA interference leads to loss of silencing of the Igf-2 gene on the
paternal chromosome and a down-regulation of Igf-2 expression. We investigate the effect of
91H on DNA methylation in ICR and differentially methylated region of this locus but also in
heterochromatin formation leading to gene silencing.
Our results indicate that 91H plays a key role in genomic imprinting at the H19/IGF2 locus
and we discuss the role of long intergenic antisense transcript in chromatin remodelling and
imprinting maintenance.
Publications:
1: Berteaux N, Lottin S, Monte D, Pinte S, Quatannens B, Coll J, Hondermarck H, Curgy JJ, Dugimont T,
Adriaenssens E. H19 mRNA-like noncoding RNA promotes breast cancer cell proliferation through positive
control by E2F1. J Biol Chem. 2005, 280:29625-36.
2: Lottin S, Adriaenssens E, Berteaux N, Lepretre A, Vilain MO, Denhez E, Coll J, Dugimont T, Curgy JJ. The
human H19 gene is frequently overexpressed in myometrium and stroma during pathological endometrial
proliferative events. Eur J Cancer. 2005, 41:168-77.
3: Berteaux N, Lottin S, Adriaenssens E, Van Coppenolle F, Leroy X, Coll J, Dugimont T, Curgy JJ. Hormonal
regulation of H19 gene expression in prostate epithelial cells. J Endocrinol. 2004, 183:69-78.
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