Developmental regulation of EphA4 expression in the chick auditory brainstem.
J Comp Neurol
; 426(2): 270-8, 2000 Oct 16.
Article
em En
| MEDLINE
| ID: mdl-10982468
ABSTRACT
The avian auditory brainstem nuclei nucleus magnocellularis (NM) and nucleus laminaris (NL) display highly precise patterns of neuronal connectivity. NM projects tonotopically to the dorsal dendrites of ipsilateral NL neurons and to the ventral dendrites of contralateral NL neurons. The precision of this binaural segregation is evident at the earliest developmental stage at which connections can be observed. We have begun to examine the possibility that Eph receptor tyrosine kinase signaling is involved in establishing these spatially segregated connections. The expression of the EphA4 tyrosine kinase was examined at several developmental stages. EphA4 is expressed in rhombomere 5, which contains progenitors for both NM and NL. In this rhombomere, the labeling becomes striped during the time that precursor cells migrate to the auditory anlage. At the precise time when NM-NL projections are forming, EphA4 expression in NL is asymmetric, with markedly higher expression in the dorsal NL neuropil than in the ventral neuropil, suggesting a possible role in guiding growing axons to the appropriate region. At later embryonic ages EphA4 expression is symmetric around NL, and is absent in NM. As auditory function matures, EphA4 expression decreases so that by 4 days after hatch no EphA4 antibody labeling is evident in the auditory brainstem nuclei.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vias Auditivas
/
Tronco Encefálico
/
Embrião de Galinha
/
Galinhas
/
Receptores Proteína Tirosina Quinases
/
Proteínas Fetais
Limite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Estados Unidos