Target protein STAT1 (Santa Cruz SC-345) was purified by chromatin immunoprecipitation from HeLaS3 (cervix epithelial adenocarcinoma) cells. The series is comprised of three biological replicates, done using ChIP-Sequencing on a Solexa machine. DNA fragments are selected for sizes in the range of 100-300 bps, then 27nts tags are sequenced from the ends of these fragments.
The sequenced tags are mapped onto the hg18 build of the human genome using the Eland application (Illumina). Only tags that map uniquely with at most two mismatches are included. 6,540,633 tags were mapped uniquely to the genome from the combined data from the three biological replicates.
Signal maps represent the cumulative heights of mapped DNA fragments (average size 200 bps) - peaks correspond to locations where multiple mapped fragments colocate.