Effect of tissue-specific deletion of survivin on polyploidization and differentiation of bone marrow megakaryocytes. Bone marrow cells from control (Sur^fl/fl and Sur^fl/+ without Cre) and PF4-Cre/Sur^fl/fl mice were collected and stained with FITC-labeled anti-CD41, PE-labeled anti-CD42, DAPI, and APC-labeled annexin V and then analyzed by flow cytometry. (A) CD41 expression, (B) CD42 expression, (C) DNA content, and (D) annexin V staining are shown. Representative flow and bar graphs depicting average ± SEM of 5 animals per group are shown. *P = .024. Note that DNA content and apoptosis are shown for only the CD41⁺ population. (E) Deletion of the floxed alleles was monitored by multiplex PCR using 3 primers to amplify the floxed (fl) and excised (ex) alleles. PCR of tail, bone marrow cells (BM), and fluorescence-activated cell sorting (FACS) purified CD41⁺ megakaryocytes (CD41⁺ BM) from 2 representative examples are shown.