A Novel H19 Antisense RNA Overexpressed in Breast Cancer Contributes to Paternal IGF2 Expression

Abstract

The H19/IGFf2 locus belongs to a large imprinted domain located on human chromosome 11p15.5 (homologue to mouse distal chromosome 7). The H19 gene is expressed from the maternal allele, while IGF2 is paternally expressed. Natural antisense transcripts and intergenic transcription have been involved in many aspects of eukaryotic gene expression, including genomic imprinting and RNA interference. However, apart from the identification of some IGF2 antisense transcripts, few data are available on that topic at the H19/IGF2 locus. We identify here a novel transcriptional activity at both the human and the mouse H19/IGF2 imprinted loci. This activity occurs antisense to the H19 gene and has the potential to produce a single 120-kb transcript that we called the 91H RNA. This nuclear and short-lived RNA is not imprinted in mouse but is expressed predominantly from the maternal allele in both mice and humans within the H19 gene region. Moreover, the transcript is stabilized in breast cancer cells and overexpressed in human breast tumors. Finally, knockdown experiments showed that, in humans, 91H, rather than affecting H19 expression, regulates IGF2 expression in trans.

SUPPLEMENTAL MATERIAL

Supplemental material for this article may be found at http://mcb.asm.org/ .

ACKNOWLEDGMENTS

We thank A. Béthouart, N. Nguyen, and C. Cathelineau for their collaboration in the collect of breast cancer tissues. We thank P. Pellerin (Lille Hospital, Lille, France) for its collaboration to collect breast normal tissues. We thank P. Delannoy (USTL, Lille, France) for the use of MX4000 apparatus and L. Brunet and G. Courtand (CCMIC and USTL) for their help with the text illustrations.

J.-J.C., E.A., and T.D. hold grants from the Fédération des Groupements des Entreprises Françaises dans la Lutte contre le Cancer, the Comités du Nord et de l'Aisne de la Ligue Nationale contre le Cancer, and the Association pour la Recherche sur le Cancer (ARC). N.B. is the recipient of fellowships from the Ministère de l'Education Nationale et de la Recherche, the ARC, and the Institut National du Cancer. This study was also supported by grants from the ARC (grant 4868), the GIS Longévité (contract GISLO401), the Fond National de la Science (ACI Jeune Chercheur), and the Agence Nationale de La Recherche (ANR-07-BLAN-0052-02 -T.F.-) and by funds from the Centre National de la Recherche Scientifique.

We dedicate this report to the memory of our friend Jean Coll.