Tenascin may not be required for intestinal villus development.

Tenascin, a large extracellular matrix protein, is subject to complex spatial and temporal patterns of expression in the course of various organogenetic processes including the formation of the small intestinal villus. In the present study, the presence of tenascin was analyzed in human fetal colonic villi, which are transient structures that are programmed to disappear at the time of colonic mucosal remodeling. While the labeling of muscles and peripheral mesenchyme was similar in both segments, surprisingly the colonic villus cores were mostly devoid of tenascin as opposed to those of the small intestine. Western blot analysis revealed that the 220 and 320 kDa forms of tenascin were detected in both segments. However, the 200 kDa form present in small intestinal villi was absent in colonic villi. These data suggest that tenascin under its 200 kDa form is not required for villus formation.