MPL and Thrombocytopenia: At P24, DNM2 deletion in platelets and MKs and/or Mpl ubiquitous deletion resulted in comparable severe thrombocytopenia with platelet counts of 111 ± 43 x 103/μl in Dnm2Plt–/–, 158 ± 53 x 103/μl in Mpl–/– Dnm2Plt+/+, and 189 ± 196 x 103/μl in Mpl–/– Dnm2Plt–/–, compared to 1243 ± 300 x 103/μl in control Dnm2Plt+/+ mice (P <.0001) (Figure 3A).