Figure 1

Expression of Notch 1–3 receptors, Delta1 and Jagged1 transmembrane ligands and of the three Fringe excreted proteins in unlesional human skin. Nuclear staining with propidium iodide (A-C, D-F, G-I) and darkfield observation of in situ hybridisation (A'-C', D'-F', G'-I') on cryosections. Radiolabelled riboprobes against Notch (A'-C') and its ligand (D'-E') genes are detected in the basal layer of the epidermis and to a lower extent in suprabasal layers. Fringe gene expression is restricted to the basal layer (G'-I'). Signals detected in the upper cornified layer with no nucleated cells correspond to artefacts caused by dense keratin and edge effects. The control (F, F') represents a skin section processed with the sense Jagged1 riboprobe under the same conditions. Scale bar, 100 μm; Ma, Manic; Lu, Lunatic; Ra, Radical; d: dermis; bl: basal layer; spl: suprabasal layer; cl: cornified layer; e: epidermis.