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.
PhD Thesis, University of Basel,
Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_9221
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.
|Committee Members:||Dehio, Christoph and Schär, Primo-Leo|
|Faculties and Departments:||05 Faculty of Science > Departement Biozentrum > Infection Biology > Molecular Microbiology (Dehio)|
|Bibsysno:||Link to catalogue|
|Number of Pages:||137 S.|
|Last Modified:||30 Jun 2016 10:41|
|Deposited On:||21 Jan 2011 10:48|
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