Differentiation of cultured palatal shelves from alligator, chick, and mouse embryos

Abstract

Palatal shelves from embryonic alligators, chicks, and mice were explanted at various stages of development and organ cultured in either chemically defined, serumless media or the same media supplemented with 10% fetal calf serum. Shelves from each vertebrate were either cultured singly or in contact, and heterologous combinations of palatal shelves from different animals were made: chick/mouse, chick/alligator, and mouse/alligator. Epithelial differentiation (particularly that of the medial shelf edge) was assayed by vital staining, histology, and scanning electron microscopy. In vitro medial edge epithelial differentiation, and consequently the mechanisms of palatal closure, were identical to those normally seen in vivo for each species, i.e., cobble-stoned migrating epithelia in the alligator, cell death and fusion in the mouse, and keratinisation and cleft palate in the chick. Differentiation was optimal in the chemically defined, serumless media and was independent of shelf contact in all three species. No heterologous combinations of palatal shelves closed with each other: Evidently, the modes of palatal closure in mice and alligators are sufficiently different to prevent them forming a chimeric palate, whilst neither is capable of inducing closure in a cocultured chick palatal shelf. These unified defined culture conditions make possible a large number of epithelial-mesenchymal recombination studies as well as specific inhibitor, teratogenic, and hormonal investigations.

Comparative ontogeny and phylogeny of the upper jaw skeleton in amniotes

“…The mere isolation of developmentally relevant coding sequences from reptiles will provide a muchneeded missing link. Oviparous species such as alligator and turtle offer opportunities for in ovo fate mapping, setting up organ cultures (inter or homospecific; Ferguson et al, 1984;Nagashima et al, 2005) or for performing experimental manipulations in ovo. Interspecific grafts would allow one to test whether conservation of tissue interactions and gene function exists between the major amniote groups.…”

Jag2‐Notch1 signaling regulates oral epithelial differentiation and palate development

“…During mammalian palate development, the initially vertically oriented palatal shelves are often in direct contact with but do not normally adhere to the mandible or the developing tongue (Shapiro and Sweney, 1969;Mato and Uchiyama, 1975;Ferguson et al, 1984). Pathological palatemandible and palate-tongue fusions, however, have been reported in humans, mice, and rats (Humphrey, 1970;Mato and Uchiyama, 1975;Shah, 1977;Jiang et al, 1998;Din, 2003;Alappat et al, 2005), suggesting that the competence for oral and palatal shelf adhesion must be spatiotemporally regulated.…”

Gene expression analysis reveals that formation of the mouse anterior secondary palate involves recruitment of cells from the posterior side

“…Following contact, the two medial edge epithelial sheets merge to form the MEE seam that will soon undergo degeneration (Ferguson 1988;Shuler et al, 1991;Shuler et al, 1992;Carette and Ferguson 1992;Griffith and Hay 1992;Murray and Schutte, 2004). This process requires the differentiation of palatal medial edge epithelial cells that are distinct from the epithelial cells on oral and nasal sides (Ferguson et al, 1984). Moreover, tissue recombination experiments revealed that the differentiation of medial epithelial cells is determined by the underlying medial edge mesenchymal cells (Ferguson et al, 1984).…”