Extended Data Fig. 3: Young LR-HSCs are located in central and endosteal BM.

a, Representative stacked whole-mount images of young SCL-tTAxH2B-GFP femoral BM showing LR cells (green) and vasculature (blue). b, 3D reconstruction of confocal whole-mount images of young SCL-tTAxH2B-GFP femoral BM showing a CD150⁺ H2B-GFP⁺ LR cell in proximity to arterial vasculature (arrowheads) in the endosteal area. c, d, Distinction of sinusoids and arterioles in (c) FABP4 (red) in situ stained and (d) CD31/CD144 (red) i.v. stained BM: arterioles (yellow arrowheads) have small diameter with continuous staining (continuous basal lamina) and have parallel orientation to the long axis of the bone, sinusoids (blue arrowheads) present relatively larger diameter with spotted staining (fenestrated basal lamina) and are mostly transverse to the long axis. (c) Nuclei, DAPI (blue). e, f, Colocalization of (e) sinusoids and (f) arterioles/arteries in FABP4 (green) in situ stained and CD31/CD144 (red) i.v. stained BM. Experiments in a-c, e, f were repeated three independent times with similar results and in d at least 9 independent times with similar results. Scale bars are 100 μm (a); 20 μm (b-f).