Temporal regulation of EphA4 in astroglia during murine retinal and optic nerve development.
Eph receptors and their ephrin ligands play important roles in many aspects of visual system development. In this study, we characterized the spatial and temporal expression pattern of EphA4 in astrocyte precursor cell (APC) and astrocyte populations in the murine retina and optic nerve. EphA4 is expressed by immotile optic disc astrocyte precursor cells (ODAPS), but EphA4 is downregulated as these cells migrate into the retina. Surprisingly, mature astrocytes in the adult retina re-express EphA4. Within the optic nerve, EphA4 is expressed in specialized astrocytes that form a meshwork at the optic nerve head (ONH). Our in vitro and in vivo data indicate that EphA4 is dispensable for retinal ganglion cell (RGC) axon growth and projections through the chiasm. While optic stalk structure, APC proliferation and migration, retinal vascularization, and oligodendrocyte migration appear normal in EphA4 mutants, the expression of EphA4 in APCs and in the astrocyte meshwork at the ONH has implications for optic nerve pathologies.
Center for Neurobiology and Behavior, Department of Pathology, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA.
Timothy J
TJ
Petros
Scott E
SE
Williams
Carol A
CA
Mason
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002450:Cell Communication / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002465:Cell Movement / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D020439:Growth Cones / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D009900:Optic Nerve / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D009924:Organ Culture Techniques; D036122:Receptor, EphA4 / Q000235:genetics* / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D013997:Time Factors
D036122:Receptor, EphA4