Transcription factor GATA-3 alters pathway selection of olivocochlear neurons and affects morphogenesis of the ear

Citation
A. Karis et al., Transcription factor GATA-3 alters pathway selection of olivocochlear neurons and affects morphogenesis of the ear, J COMP NEUR, 429(4), 2001, pp. 615-630
Citations number
55
Categorie Soggetti
Neurosciences & Behavoir
Journal title
JOURNAL OF COMPARATIVE NEUROLOGY
ISSN journal
00219967 → ACNP
Volume
429
Issue
4
Year of publication
2001
Pages
615 - 630
Database
ISI
SICI code
0021-9967(20010122)429:4<615:TFGAPS>2.0.ZU;2-B
Abstract
Patterning the vertebrate ear requires the coordinated expression of genes that are involved in morphogenesis, neurogenesis, and hair cell formation. The zinc finger gene GATA-3 is expressed both in the inner ear and in affer ent and efferent auditory neurons. Specifically, GATA-3 is expressed in a p opulation of neurons in rhombomere 4 that extend their axons across the flo or plate of rhombomere 4 (r4) at embryonic day 10 (E10) and reach the senso ry epithelia of the ear by E13.5. The distribution of their cell bodies cor responds to that of the cell bodies of the cochlear and vestibular efferent neurons as revealed by labeling with tracers. Both GATA-3 heterozygous and GATA-3 null mutant mice show unusual axonal projections, such as misrouted crossing fibers and fibers in the facial nerve, that are absent in wild-ty pe littermates. This suggests that GATA-3 is involved in the pathfinding of efferent neuron axons that navigate to the ear. In the ear, GATA-3 is expr essed inside the otocyst and the surrounding periotic mesenchyme. The latte r expression is in areas of branching of the developing ear leading to the formation of semicircular canals. Ears of GATA-3 null mutants remain cystic , with a single extension of the endolymphatic duct and no formation of sem icircular canals or saccular and utricular recesses. Thus, both the distrib ution of GATA-3 and the effects of null mutations on the ear suggest involv ement of GATA-3 in morphogenesis of the ear. This study shows for the first time that a zinc finger factor is involved in axonal navigation of the inn er ear efferent neurons and, simultaneously, in the morphogenesis of the in ner ear. J. Comp. Neurol. 429:615-630, 2001. (C) 2001 Wiley-Liss, Inc.