Apical ectodermal ridge

Robert, B., Lyons, G., Simandle, B. K., Kuroiwa, A., and Buckingham, M. (1991). The apical ectodermal ridge regulates Hox-7 and Hox-8 gene expression in developing chick limb buds. Genes Dev. 5 2363-2374. 

Laufer, E., Dahn, R., Orozco, O.E., Yeo, C-Y., Pisenti, J., Henriques, D., Abbott, U.K., Fallon, J.F., Tabin, C. (1997). Expression of Radical fringe in limb-bud ectoderm regulates apical ectodermal ridge formation. Nature (London) 386,366-373. 

Rodriguez-Esteban, C., Schwabe, J.W.R., De La Pena, J., Foys, B Esheiroan, B., Izpisua-Belmonte, J.C. (1997). Radical fringe positions the apical ectodermal ridge at the dorsoventral boundary of the vertebrate limb. Nature (London) 386,360-365. 

Saunders, J.W., Gasseling, M.T., Cairns, J.M. (1959). Differentiation of prospective thigh mesoderm grafted beneath the apical ectodermal ridge of the wing in the chick embryo. Dev Biol. 1,281 -301. 

Niswander, L., Tickle, C., Vogel, A., Booth, I., and Martin, G. R., FGFA replaces the apical ectodermal ridge and directs outgrowth and patterning of the limb, Cell, 75, 579, 1993. 

Sumoy, L., Wang, C.K., Lichtler, A.C., Pierro, L.J., Kosher, R.A., Upholt, W.B. 1995. Identification of a spatially specific enhancer element in the chicken Msx-2 gene that regulates its expression in the apical ectodermal ridge of the developing limb buds of transgenic mice. Dev. Biol. 170, 230-242. 

Ferrari, D., Sumoy, L., Gannon, J., Sun, H., Brown, A.M., Upholt, W.B., Kosher, R.A. 1995. The expression pattern of the Distal-less homeobox-containing gene Dlx-5 in the developing chick limb bud suggests its involvement in apical ectodermal ridge activity, pattern formation, and cartilage differentiation. Mech. Dev. 52, 257-264. 

Apical ectodermal ridge Zone of polarising activity... 

Fig. 3. (A) (Subheading 3.2.) Diagrams to show how an apical ridge is isolated and grafted to the dorsal surface of a limb bud. Remove thin sliver of donor limb bud tip, and soak in 2% trypsin at 4°C for 5-10 min. Separate apical ectodermal ridge, and keep in ice-cold medium Graft ridge to sUt made in dorsal surface of host limb bud, and poke into place with blunt needle.

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