DMS morphology depends on the stiffness of the medium. (A) Electron microscopy images of stage III BM MKs (in situ) or MKs differentiated for 3 days in liquid or 2% MC cultures (class 3). Scale bar = 2 µm. Images are representative of at least 4 mice (in situ) or 10 cultures. (B) Left, electron microscopy image of an MK differentiated for 3 days in 2% MC and resuspended in a liquid medium for 2 hours before fixation (representative of 3 independent experiments with >90 MKs examined). Right, close-up view of the cytoplasm of the MK. (C) Left, electron microscopy image of an MK from BM after dissociation and resuspension for 2 hours in a liquid medium (representative of 3 independent experiments with >90 MKs examined). Right, close-up view of the cytoplasm of the MK.