Expression domains of murine ephrin-A5 in the pituitary and hypothalamus

Using in situ hybridization on whole-mounts and sections of mouse embryos w e have visualized the pattern of expression for the Eph receptor ligand eph rin-A5. Non neuronal expression domains include the ectoderm of the branchi al arches, the ectoderm and mesenchyme surrounding the dorsal root ganglia, the intervertebral discs, maxillary and mandibulary mesenchymal elements a s well as the nasal mesenchyme and ectoderm. Within the developing nervous system, ephrin-A5 expression is very dynamic. Besides the midbrain it is al so expressed in the hypothalamus, and the neurohypohysis that we studied he re in more detail. Hypothalamus expression of ephrin-A5 demarks distinct nu clei, persists throughout embryonic development, and can be seen also in th e adult. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.