Video 2.

S1pr1^+/+ MKs extend PPs preferentially into BM sinusoids, whereas S1pr1-deficient MKs display PP extensions into the BM interstitium. Intravital two-photon imaging of EGFP⁺ MKs (green) and vasculatures (red) in calvarial BM of an S1pr1^+/+; lenti-GPIbα-EGFP or S1pr1^−/−; lenti-GPIbα-EGFP BM chimaeras or naive (nontransplanted) CD41-YFP^ki/+ S1pr1^+/+ mice or naive (nontransplanted) CD41-YFP^ki/+ S1pr1^+/− mice. The 3D video was reconstructed from a stack of x-y sections at axial (z) spacing of 3 µm with a rotation from −30° to 30°. The arrowheads indicate EGFP⁺ or YFP⁺ PPs. Bar, 20 µm.

A novel role of sphingosine 1-phosphate receptor S1pr1 in mouse thrombopoiesis

Lin Zhang, Martin Orban, Michael Lorenz, Verena Barocke, Daniel Braun, Nicole Urtz, Christian Schulz, Marie-Luise von Brühl, Anca Tirniceriu, Florian Gaertner, Richard L. Proia, Thomas Graf, Steffen-Sebastian Bolz, Eloi Montanez, Marco Prinz, Alexandra Müller, Louisa von Baumgarten, Andreas Billich, Michael Sixt, Reinhard Fässler, Ulrich H. von Andrian, Tobias Junt, and Steffen Massberg

DOI: 10.1084/jem.20121090