Fig. 6. Progeny of the serosal mesothelium differentiate into vascular smooth muscle cells. (A-H) Immunohistochemistry for ß-Gal and vessel markers in the adult gut. In co-labeling studies for ß-Gal and SMA (A), or ß-Gal and Pecam (E), the anti-ß-Gal antibody marks blood vessels (asterisks) and the serosal mesothelium (arrowheads; A,E), but not the visceral smooth muscle (vism) of the intestine (A). High magnification (white box in A) of anti-SMA and anti-ß-Gal staining reveals colocalization of ß-Gal and SMA (arrowheads, B-D). Note the additional ß-Gal-marked cells interspersed (arrows) between circular (cvm) and longitudinal visceral smooth muscle layers (lvm). High magnification (white box in E) of anti-Pecam and anti-ß-Gal staining shows virtually no overlap of expression (arrowheads, F-H). Note that ß-Gal-marked cells are arranged perpendicular to the endothelial Pecam-positive cells. Scale bars: in A, 50 µm for A,E; in B, 30 µm for B-D,F-H.