C3G regulates megakaryocyte motility and promotes the formation of proplatelets. a Transverse sections of bone marrows from the different genotypes were plated in an incubation chamber and maintained at 37 °C for 6 h. MKs at the periphery of the explants were tracked under the microscope and images were acquired at 10 min intervals. Upper box plots represent the median ± SEM velocity (μm/second) of individual megakaryocytes 6 h after their release from bone marrow explants. Lower box plots represent the median distance (μm) covered by megakaryocytes from bone marrow explants. Three mice of each genotype were analyzed. Mann Whitney U test were done. **p < 0.01, ***p < 0.001. b Percentage of MKs most strongly associated to the osteoblastic niche. After extraction of the bone marrow, small pieces of femur were treated with collagenase and dispase for 2 h and the percentage of CD61+ cells was analyzed by flow cytometry. Mann-Whitney U test was done. c Representative images of the different stages of MK maturation: spherical megakaryocytes, megakaryocytes with extending protrusions and megakaryocytes with proplatelets. Fluorescence microscope images (Left panels) and brightfield inverted microscope images (right panels). The histograms represent the mean ± SEM of the percentage of cells of each phenotype measured in two different experiments, with at least 4 explants from each genotype. d C3G did not modify platelet count. Counts were performed in peripheral blood collected from 6-month mice of the different genotypes using Hemavet Counter HV950FS. The histograms represent the mean ± SEM of the number of platelets. Mann-Whitney U test was done, but no significant differences were observed between Tg-C3G or Tg-C3GΔCat vs WT.