JAGGED2 - A PUTATIVE NOTCH LIGAND EXPRESSED IN THE APICAL ECTODERMAL RIDGE AND IN SITES OF EPITHELIAL-MESENCHYMAL INTERACTIONS

The Drosophila Notch gene and its ligands, Delta and Serrate, are invo lved in cell fate determination in a variety of-developing tissues. Re cently, several Notch, Delta and Serrate homologues have been identifi ed in vertebrates. We report here the cloning of the human and murine JAGGED2 (JAG2), a Serrate-like gene, and the analysis of its expressio n pattern during embryogenesis. Jag2 was found to be expressed as earl y as E9 in the surface ectoderm of the branchial arches and in the api cal ectodermal ridge (AER) of the developing limb. At E12.5, Jag2 expr ession is upregulated in differentiated neurons of the central and per ipheral nervous system and in the inner neuroblastic layer of the deve loping retina. Outside the nervous system, Jag2 is expressed in the de veloping vibrissae follicles, tooth buds, thymus, submandibular gland and stomach. Our findings suggest the involvement of Jagged2 in the de velopment of the mammalian limb, branchial arches, central and periphe ral nervous systems and several tissues whose development depends upon epithelial-mesenchymal interactions. (C) 1997 Elsevier Science Irelan d Ltd.