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⁻Fli1^fl/Fli1^fl 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⁻Fli1^fl/Fli1^fl 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.