Expression of EphA4 in developing inner ears of the mouse and guinea pig.
The expression of EphA4, an Eph-class receptor tyrosine kinase, was determined by immunohistochemistry in developing inner ears of the mouse and the guinea pig. In the mouse, EphA4 expression was visible in the fibroblasts of the spiral ligament and in the structures that were to become the osseous spiral lamina. Cochlear nerve ganglion cells expressed ephrin-B2, and the modiolus expressed mRNA coding for ephrin-B3, both transmembrane ligands for EphA4. In contrast, in the guinea pig, cells of the cochlear nerve ganglion expressed EphA4, as did supporting cells of the organ of Corti (Hensen's cells and inner pillar cells). There was also some expression in fibroblasts of the spiral ligament but none in the structures that were to become the osseous spiral lamina. It is suggested that in the mouse, EphA4 may help direct the cochlear innervation towards the organ of Corti by a repulsive interaction, but that this is highly species dependent.
van Heumen
W R
WR
Vision, Touch and Hearing Research Centre, Department of Physiology and Pharmacology, University of Queensland, Brisbane, Australia.
Claxton
C
C
Pickles
J O
JO
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D003053:Cochlear Duct / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D003056:Cochlear Nerve / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D007758:Ear, Inner / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism*; D036388:Ephrin-B2; D005326:Fetal Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006168:Guinea Pigs; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D036122:Receptor, EphA4
D017931:DNA Primers; D036388:Ephrin-B2; D005326:Fetal Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D036122:Receptor, EphA4