Fli-1 gene deletion induces a mild thrombocytopenia associated with megakaryocytes maturation defects and drastic decrease in CFU-MK numbers. (A) Representative fields of BMCs cytospins from pIpC-injected Cre+ and Cre−Fli1fl/Fli1fl mice. Arrows indicate representative mature and immature megakaryocytes in Cre− or Cre+ cytospins, respectively. (B) Histogram showing significant inverted proportions of immature versus mature megakaryocytes in bone marrow between injected Cre+ or Cre− mice (P = 1.48 × 10−5 and 4.1 × 10−6 for immature and mature cells, respectively). Means and SDs from 5 different couples of injected Cre+ and Cre−Fli1fl/Fli1fl mice. (C) Diagram showing the variations in platelet numbers with respect of the extent of Fli-1 gene deletion. Dotted line and gray area indicates the mean and SD of platelet numbers in injected control Cre− mice. (D) Diagram showing the variations in CFU-MK numbers for 5 × 104 BMCs with respect of the extent of Fli-1 gene deletion (a total of 2 × 105 BMCs have been plated for each experiment). Dotted line and gray area indicate the mean and SD of CFU-MK numbers in injected control Cre− mice.