DISTRIBUTION OF EPH-RELATED MOLECULES IN THE DEVELOPING AND MATURE COCHLEA

Receptors and ligands of the Eph family have recently been shown to in fluence the development of a variety of tissues. In the present study, the temporal and spatial distribution of Eph receptors and ligands we re investigated in the embryonic and postnatal cochlea using Northern blot and immunohistochemical analysis. The results of Northern blot ex periments revealed that a large number of Eph family members were pres ent in embryonic cochlear and vestibular ganglia. Immunohistochemical studies revealed that ligands and receptors of the GPI subclass were d istributed in complementary patterns within the differentiating spiral limbus, inner sulcus and outer sulcus. The distribution of these mole cules became more restricted beginning in the first postnatal week. In contrast, members of the transmembrane subclass of Eph ligands were l argely associated with cochlear neurons and their target hair cells. E xpression of these ligands appeared to increase during the second post natal week, corresponding to the period of peripheral nerve fiber reor ganization in the cochlea. Together, these studies suggest that multip le Eph family members play unique roles in formation of the cochlea. ( C) 1998 Published by Elsevier Science B.V.