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Enhanced transcription of the IFN-alpha inducible gene IFITM3 by means of dynamic promoter demethylation in the presence of the TGF-beta inducible small calcium binding protein S100A2

Woodward Scott, Rachel. Enhanced transcription of the IFN-alpha inducible gene IFITM3 by means of dynamic promoter demethylation in the presence of the TGF-beta inducible small calcium binding protein S100A2. 2010, PhD Thesis, University of Basel, Faculty of Science.

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Official URL: http://edoc.unibas.ch/diss/DissB_9221

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Abstract

In human melanoma cell lines, the calcium binding protein S100A2 augments the antiproliferative activity of interferon-alpha (IFN) by an unknown mechanism. I show by microarray profiling that recombinant over-expression of S100A2 upregulates the expression of a subset of IFNα response genes beyond the maximal cytokine inducible level including IFITM3, a gene with documented antiproliferative activity. I have chosen IFITM3 as chromosomal IFN response reporter gene in a model system consisting of two human melanoma cell lines ME15 and D10 described previously (Brem, Oraszlan-Szovik et al. 2003). In ME15 cells IFITM3 expression is strictly IFN dependent whilst it is constitutively expressed in the IFN resistant D10 cells. It was shown that S100A2 is sufficient to restore IFN sensitivity in D10 (Foser, Redwanz et al. 2006) and I show by indirect immunofluorescence cytoplasmic localization of S100A2, which eliminates a direct function as a transcriptional enhancer of IFITM3 expression and other antiproliferative genes. I show that treatment of ME15 melanoma cells with the demethylating agent 5-aza-2’deoxycytidine (DAC) results in a significant increase of IFITM3 expression following IFNα stimulation suggesting a DNA methylation mediated mechanism. Based on bisulfite sequencing of the IFITM3 core promoter, I show that D10 cells exhibit hypomethylation and I demonstrate that S100A2 is required for kinetic and reversible IFN induced CpG demethylation in ME15 cells. Since p53 signaling is not functional in D10 cells I propose an indirect mechanism of methylation that involves p53 controlled signaling pathways.
Advisors:Certa, Ulrich
Committee Members:Dehio, Christoph and Schär, Primo-Leo
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Infection Biology > Molecular Microbiology (Dehio)
Item Type:Thesis
Thesis no:9221
Bibsysno:Link to catalogue
Number of Pages:137 S.
Language:English
Identification Number:
Last Modified:30 Jun 2016 10:41
Deposited On:21 Jan 2011 10:48

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