Abstract
Two ligands for Eph-related receptor tyrosine kinases, RAGS and ELF-1, have been implicated in the control of development of the retinotectal projection. Both molecules are expressed in overlapping gradients in the tectum, the target area of retinal ganglion cell axons. In two in vitro assays ELF-1 is shown to have a repellent axon guidance function for temporal, but apparently not for nasal axons. RAGS on the other hand is repellent for both types of axons, though to different degrees. Thus, RAGS and ELF-1 share some and differ in other properties. The biological activities of these molecules correlate with the strength of interaction with their receptors expressed on RGC axons. The meaning of these findings for guidance of retinal axons in the tectum is discussed.
MeSH terms
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Animals
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Axons / metabolism*
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Base Sequence
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COS Cells
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Chick Embryo
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DNA Primers / genetics
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DNA, Complementary / genetics
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Ephrin-A2
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Gene Expression Regulation, Developmental
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In Vitro Techniques
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Mice
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Nuclear Proteins
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RNA / genetics
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RNA / metabolism
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Receptor Protein-Tyrosine Kinases / metabolism
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Retina / cytology
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Retina / embryology*
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Retina / metabolism
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Retinal Ganglion Cells / metabolism*
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Superior Colliculi / cytology
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Superior Colliculi / embryology
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Superior Colliculi / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transfection
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Visual Pathways / cytology
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Visual Pathways / embryology
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Visual Pathways / metabolism
Substances
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DNA Primers
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DNA, Complementary
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DNA-Binding Proteins
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ELF1 protein, human
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Elf1 protein, mouse
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Ephrin-A2
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Nuclear Proteins
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Transcription Factors
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RNA
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Receptor Protein-Tyrosine Kinases