... Mesenchyme Apical ectodermal ridge Wnt7a Lmx-1 Dorsal ectoderm Eph receptors constitute the largest subfamily of receptor tyrosine kinases, with 14 members already described. These receptors and their ligands, the ephrins, have been recently attributed key roles in regionalisation, cell migration...

... previously shown that the limbs of En1 mutant mice display dorsal-ventral and proximal-distal abnormalities, the latter being reflected in the appearance of a broadened AER and formation of ectopic ventral digits. A detailed genetic analysis of wild-type, En1 and Wnt7a mutant limb buds during AER development...

... in the mutant limb buds. Thus, some aspects of mesoderm A-P patterning can occur in the absence of SHH and factors normally expressed in the apical ridge. Intriguingly, mutant limbs rescued by local application of FGF displayed a dorsalized feather pattern. Furthermore, the expression of Wnt7a, Lmx1 and En1...