HMGA2 regulates transcription of the Imp2 gene via an intronic regulatory element in cooperation with nuclear factor-kappaB.
IMP2 (insulin-like growth factor-II mRNA binding protein 2) is an oncofetal protein that is aberrantly expressed in several types of cancer. We recently identified the Imp2 gene as a target gene of the architectural transcription factor HMGA2 (high mobility group A2) and its tumor-specific truncated form HMGA2Tr. In this study, we investigated the mechanism via which HMGA2 regulates Imp2 gene expression. We show that HMGA2 and HMGA2Tr directly regulate transcription of the Imp2 gene by binding to an AT-rich regulatory region located in the first intron. In reporter experiments, we show that this AT-rich regulatory region mimics the response of the endogenous Imp2 gene to HMGA2 and HMGA2Tr. Furthermore, we show that a consensus nuclear factor-kappaB (NF-kappaB) binding site located immediately adjacent to the AT-rich regulatory region binds NF-kappaB and that NF-kappaB and HMGA2 cooperate to regulate Imp2 gene expression. Finally, we provide evidence that there is a strong and statistically significant correlation between HMGA2 and IMP2 gene expression in human liposarcomas.
Cleynen
Isabelle
I
Department of Human Genetics, Flanders Interuniversity Institute for Biotechnology, University of Leuven, Herestraat 49, Box 602, B-3000 Leuven, Belgium.
Brants
Jan R
JR
Peeters
Kristel
K
Deckers
Rob
R
Debiec-Rychter
Maria
M
Sciot
Raf
R
Van de Ven
Wim J M
WJ
Petit
Marleen M R
MM
D020856:AT Rich Sequence; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D005260:Female; D025743:HMGA2 Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007438:Introns; D008080:Liposarcoma / Q000378:metabolism*; D008297:Male; D051379:Mice; D008875:Middle Aged; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D041681:NIH 3T3 Cells; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D050436:Regulatory Elements, Transcriptional; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
D025743:HMGA2 Protein; C498779:IGF2BP2 protein, human; D016328:NF-kappa B; D016601:RNA-Binding Proteins