AZD1152-HQPA inhibits histone H3 Ser10 phosphorylation in MKs. (A) A dose-response curve showing inhibition of histone H3 phosphorylation (H3PP) in MKs at day 7 of culture after 48 hours of exposure to AZD1152-HQPA. (B) Flow cytometry was used to determine percentage of cells with phosphorylated histone H3. The plots show propidium iodide staining, used to show the DNA content of cells against the level of phosphorylated histone H3 for each cell measured. At 48 hours, the untreated population had 9% phosphorylated histone H3 (TPO) and AZD1152-HQPA treated cells (100nM) 4.6% (TPO + AZD1152-HQPA) shown in the selected region on these plots.