Abstracts (poster) - Wissenschaft Online

Christian Schmidl, Maja Klug, Tina Böld, Petra Hoffmann, Matthias Edinger, Michael
Rehli
Locus-wide detection of cell type specific DNA methylation
patterns using comparative methyl-CpG-Immunoprecipitation
(MCIp)
DNA-methylation is a vital epigenetic mark. It participates in establishing and
maintaining chromatin structures and regulates gene transcription during mammalian
development and cellular differentiation. The extent, function and regulation of tissue- or
cell type-specific DNA-methylation, however, is largely unknown. Here we present a
locus-wide DNA-methylation analysis of CD4+CD25+ regulatory T-cells (Treg) and
conventional CD4+CD25- T-cells (Tconv). Comparative methylation profiling was
performed by fractionation of genomic DNA in hyper- and hypomethylated subsets using
methyl-CpG-immuno precipitation (MCIp) followed by microarray hybridisation and
combined analysis. In total, 69 genomic regions (124 genes and covering 12 Mb of the
human genome) that were selected based on differential gene expression in both cell
types, were analysed for differentially methylated areas. Microarray results were
independently validated using qPCR and/or bisulfite sequencing. In total, we detected
approximately 130 locations that were specifically demethylated in one or the other cell
type (appr. 100 in Treg, 30 in Tconv). Such areas are detected in almost 2/3rds of the
analysed regions, particularly in cell-type specific genes like FOXP3, IL2RA and IKZF2 in
Tregs or CD40LG and IFNG in Tconv. Interestingly, the majority of cell-type specifically
demethylated areas overlap with evolutionary conserved sequences suggesting
regulatory functions for these areas. Our pilot study demonstrates the feasibility of our
approach for exploring genome-wide methylation differences in normal cells and
provides a first comprehensive, locus-wide analysis of cell type-specific methylation
patterns in regulatory T-cells and conventional CD4+ T-cells.
contact:
Christian Schmidl
Uniklinikum Regensburg
Hämatologie/Onkologie
christian.schmidl@klinik.uni-regensburg.de
Franz-Josef-Strauss Allee 11
93053 Regensurg (Deutschland)