Fig. 8. Intravital two-photon microscopy of bone marrow megakaryocytes in live mouse calvarium.

Bone marrow vasculature was visualized by intravenous injection of anti-CD105-AlexaFluor 546 antibody and AlexaFluor 546-labelled BSA (red). Megakaryocytes (MKs) and their derivatives were stained intravenously with anti-GPIX-AlexaFluor 488 antibody (cyan). Both wild-type (WT) and Tropomyosin 4^−/− (Tpm4^−/−) MKs were generally seen in close contact with the bone marrow sinusoidal walls. Images were taken from n = 6 biologically independent mice for each group (WT and Tpm4^−/−). Scale bars, 50 µm. a Representative images of large fragments of WT and Tpm4^−/− MKs (white arrows) within sinusoidal vessels releasing heterogeneous structures in the direction of blood flow, at time points indicated. b Representative images of WT and Tpm4^−/− MKs, with cell bodies within the marrow space, producing extensions into sinusoids (yellow arrowheads). c Representative images of WT and Tpm4^−/− MKs within the sinusoid, showing cellular extensions (white circles).