For ChIP-chip experiments, 5 x 107 C6 glioma cells were cultured to 90% confluence. Cells were treated with 1% formaldehyde, and the cross-linked chromatin was sonicated (average size, 300 bp). Immunoprecipitation were performed with components of the ChIP IT kit according to the manufacturer’s instructions (Active Motif, Carlsbad, CA). Each sample was immunoprecipitated with 1 µg of anti-H3K4me3 antibody (Millipore). The amount and quality of immunoprecipitated DNA were determined by capillary electrophoresis with a Bioanalyzer 2100 and a High Sensitivity DNA LabChip kit from Agilent Technologies (Santa Clara, CA). Samples were amplified using the ChIP-Seq DNA sample prep kit from Illumina, following the manufacturer's instructions, and sequenced using the Ilumina HiSeq 2000 (University of Uppsala Genomic). Center).