Ephrin-A5 (AL-1/RAGS) is essential for proper retinal axon guidance and topographic mapping in the mammalian visual system.
Neuron
; 20(2): 235-43, 1998 Feb.
Article
em En
| MEDLINE
| ID: mdl-9491985
ABSTRACT
Ephrin-A5 (AL-1/RAGS), a ligand for Eph receptor tyrosine kinases, repels retinal axons in vitro and has a graded expression in the superior colliculus (SC), the major midbrain target of retinal ganglion cells. These properties implicate ephrin-A5 in the formation of topographic maps, a fundamental organizational feature of the nervous system. To test this hypothesis, we generated mice lacking ephrin-A5. The majority of ephrin-A5-/- mice develop to adulthood, are morphologically intact, and have normal anterior-posterior patterning of the midbrain. However, within the SC, retinal axons establish and maintain dense arborizations at topographically incorrect sites that correlate with locations of low expression of the related ligand ephrin-A2. In addition, retinal axons transiently overshoot the SC and extend aberrantly into the inferior colliculus (IC). This defect is consistent with the high level of ephrin-A5 expression in the IC and the finding that retinal axon growth on membranes from wild-type IC is inhibited relative to that on membranes from ephrin-A5-/- IC. These findings show that ephrin-A5 is required for the proper guidance and mapping of retinal axons in the mammalian midbrain.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nervo Óptico
/
Células Ganglionares da Retina
/
Axônios
/
Fatores de Transcrição
/
Colículos Superiores
Tipo de estudo:
Guideline
Limite:
Animals
Idioma:
En
Revista:
Neuron
Ano de publicação:
1998
Tipo de documento:
Article