Visualization of <i>OEC</i> Mediated Cre Reporter Expression Inside the Bone Marrow.

<p>(<b>A–C</b>) In addition to activating Cre reporter expression (shown in white) in cells of the osteoblast lineage, <i>OEC</i> mice resulted in the broad marking of non-hematopoietic cells within the bone marrow compartment. (<b>A’–C’</b>) Hematoxylin counterstained tissue sections corresponding to images A–C. At progressively higher levels of magnification (<b>B</b> and <b>C</b>, yellow dashed box regions), Cre reporter expression is observed in cells that contribute to the stroma throughout the bone marrow. (<b>C, C’</b>) At high magnification many Cre reporter expressing cells retain long narrow processes reminiscent of bone marrow reticular cells and line vascular sinuses. (D) Expression of the Osterix EGFPCre reporter was not detected in trabecular bone osteoblasts or bone marrow in 6 week old femurs. However, expression of Osterix was detected by immunostaining in trabecular bone osteoblasts and osteocytes (E).