Illumina sequencing of Human H3K9me3 genomic fragment library
           CD4+ T cells were purified from human blood using human CD4+ T cell isolation kit II kits (Miltenyi). The cells were digested with MNase to generate mainly mononucleosomes with minor fraction of dinucleosomes for histone modification mapping. For mapping enzyme target sites, the cells were crosslinked with formaldehyde treatment and chromatin fragmented to 200 to 300 bp by sonication. Chromatin from 2.0E+7 cells was used for each ChIP experiment, which yielded approximately 200 ng of DNA. The ChIP DNA ends were repaired using PNK and Klenow enzyme, followed by treatment with Taq polymerase to generate a protruding 3' A base used for adaptor ligation. Following ligation of a pair of Solexa adaptors to the repaired ends, the ChIP DNA was amplified using the adaptor primers for 17 cycles and the fragments around 220 bp (mononucleosome + adaptors) isolated from agarose gel. The purified DNA was used directly for cluster generation and sequencing analysis using the Solexa 1G Genome Analyzer following manufacturer protocols.         