Histone modifications on c-Mpl are Ott1-dependent and inhibitors manipulate alternative splicing. (A) H4-Acetylation of WT and Ott1 KO bone marrow. ChIP using anti-pan-acetyl-H4 on pIpC-induced Ott1 WT or Ott1flox/nullMx1-cre (Ott1 KO) adult lineage–depleted bone marrow and then quantified using qPCR to determine relative enrichment. (B) H3K4me3 of WT and Ott1 KO bone marrow. ChIP using anti-pan-H3K4me3 on pIpC-induced Ott1 WT or Ott1flox/nullMx1-cre (Ott1 KO) adult lineage–depleted bone marrow and then quantified using qPCR to determine relative enrichment (n = 3; error bars, ± SD). (C) Ratio of Mpl-TR:Mpl-FL after Hdac and/or HMT inhibitor treatment. Thpo-cultured WT fetal livers were incubated for 24 hours with control (n = 6), 100 nm chaetocin (n = 6), 5 mM sodium butyrate (n = 7), or 5 µM MS-275 (n = 4). qPCR was performed on total RNA from isolated megakaryocytes to determine Mpl-TR:Mpl-FL isoform ratio.