Chromatin immunoprecipitation analysis of Cdk8 was performed using cross-linked chromatin from 1 x 106 HCT116 colon carcinoma cells treated with serum for 0, 15, 30, and 60 minutes. Immunoprecipitation was performed using a multiplex microplate Matrix ChIP assay (see reference for Matrix ChIP protocol: http://www.ncbi.nlm.nih.gov/pubmed/22098709) with 1.0 µL/100 µL well volume of a Cdk8 polyclonal antibody (Product # PA1-21780). Chromatin aliquots from ~1 x 105 cells were used per ChIP pull-down. Quantitative PCR data were done in quadruplicate using 1 µL of eluted DNA in 2 µL SYBR real-time PCR reactions containing primers to amplify -15kb upstream of the Egr1 gene or exon-1 of Egr1. PCR calibration curves were generated for each primer pair from a dilution series of sheared total genomic DNA. Quantitation of immunoprecipitated chromatin is presented as signal relative to the total amount of input chromatin. Results represent the mean +/- SEM for three experiments. A schematic representation of the Egr-1 locus is shown above the data where boxes represent exons (black boxes = translated regions, white boxes = untranslated regions); the zigzag line represents an intron; and the straight line represents upstream sequence. Regions amplified by Egr-1 primers are represented by black bars. Data courtesy of the Innovators Program.