Nucleic Acids Research Advance Access originally published online on January 12, 2009
Nucleic Acids Research 2009 37(5):1486-1500; doi:10.1093/nar/gkn1085
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Nucleic Acids Research, 2009, Vol. 37, No. 5 1486-1500
© 2009 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Gene Regulation, Chromatin and Epigenetics |
Modulation of gene expression in U251 glioblastoma cells by binding of mutant p53 R273H to intronic and intergenic sequences
2
in
árová2
1Department of Tumor Virology, Heinrich-Pette-Institute for Experimental Virology and Immunology, D-20251 Hamburg, Germany, 2Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics AVR v.v.i., 61265 Brno, Czech Republic and 3Leeds Institute of Molecular Medicine, Section of Experimental Haematology, Wellcome Trust Brenner Building, St. James's University Hospital, Leeds, UK
*To whom correspondence should be addressed. Tel: +49 40 48051 261; Fax: +49 40 48051 117; Email: wolfgang.deppert{at}hpi.uni-hamburg.de Correspondence may also be addressed to Genrich V. Tolstonog. Tel: +49 40 48051 235; Fax: +49 40 48051 117; Email: genrich.tolstonog{at}hpi.uni-hamburg.de
Received November 12, 2008. Revised November 22, 2008. Accepted December 23, 2008.
Missense point mutations in the TP53 gene are frequent genetic alterations in human tumor tissue and cell lines derived thereof. Mutant p53 (mutp53) proteins have lost sequence-specific DNA binding, but have retained the ability to interact in a structure-selective manner with non-B DNA and to act as regulators of transcription. To identify functional binding sites of mutp53, we established a small library of genomic sequences bound by p53R273H in U251 human glioblastoma cells using chromatin immunoprecipitation (ChIP). Mutp53 binding to isolated DNA fragments confirmed the specificity of the ChIP. The mutp53 bound DNA sequences are rich in repetitive DNA elements, which are dispersed over non-coding DNA regions. Stable down-regulation of mutp53 expression strongly suggested that mutp53 binding to genomic DNA is functional. We identified the PPARGC1A and FRMD5 genes as p53R273H targets regulated by binding to intronic and intra-genic sequences. We propose a model that attributes the oncogenic functions of mutp53 to its ability to interact with intronic and intergenic non-B DNA sequences and modulate gene transcription via re-organization of chromatin.