Adhesion of medial edge epithelium cells is altered in the absence of Transforming Growth Factor beta(3)

Mutations of the gene of Transforming growth factor beta 3 (TGF-beta (3)) l ead to cleft palate in both humans and mice. This cleft seems to be produce d by a defect in the adhesion of opposing medial edge epithelia (MEE) when contact between palatal shelves occurs. Using immunohistochesmistry, we dem onstrate here that intercellular adhesion is altered in MEE cells of TGF-be ta (3) null mutant mice. The most striking features observed in these palat es are the irregular distribution of beta -catenin in the cytoplasm, in con trast to the regular and circumferential location found in wild type embryo s, and the different expression of vinculin and beta -actin, which is simil ar to the observed in the wild type oral palatal epithelium, that does not participate in palatal fusion.