Analysis of TME binding proteins in rat megakaryocytes. ChIP assays were performed using the purified rat megakaryocytes. Antibodies for PBXs or isotype-matched control were used. Precipitated DNA fragments were amplified by PCR with primers specific for the rat PF4 promoter (-300 to -182), including the TME (-219 to -182). PCR products were separated on a 2% agarose gel and stained by ethidium bromide. The intensity of each band was evaluated by Scion Image. (–) indicates no antibody.