Fig. 5. Lateral plate mesoderm does not contribute to SMCs in the anterior and middle part of the descending aorta in adult mice. (A-F) Adult descending aorta from Hoxb6-cre/R26 reporter mice was stained for lacZ activity at different anterior-posterior levels (levels are indicated in A). lacZ staining was restricted to endothelial cells in the anterior and middle part of the vessel (B-D). In posterior parts of the vessel, expression was frequently found in SMCs and endothelial cells (E,F). Boxed areas in B,C show lacZ-expressing endothelial cells at higher magnification to confirm successful staining. Arrows, SMC; arrowheads, endothelial cells; al, aortic lumen; ra, renal artery; ia, iliac artery; m, media. Scale bars: 25 µm.