Misexpression of the Emx-related homeobox genes cVax and mVax2 ventralizes the retina and perturbs the retinotectal map.
The mechanisms that establish the dorsal-ventral (D-V) axis of the eye are poorly understood. We isolated two homeobox genes from mouse and chicken, mVax2 and cVax, whose expression during early eye development is restricted to the ventral retina. In chick, ectopic expression of either Vax leads to ventralization of the early retina, as assayed by expression of the transcription factors Pax2 and Tbx5, and the Eph family members EphB2, EphB3, ephrinB1, and ephrinB2, all of which are normally dorsally or ventrally restricted. Moreover, the projections of dorsal but not ventral ganglion cell axons onto the optic tectum showed profound targeting errors following cVax misexpression. mVax2/cVax thus specify positional identity along the D-V axis of the retina and influence retinotectal mapping.
Schulte
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D
Department of Genetics and Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Furukawa
T
T
Peters
M A
MA
Kozak
C A
CA
Cepko
C L
CL
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D030161:Avian Proteins; D002642:Chick Embryo / Q000502:physiology; D003001:Cloning, Molecular; D005314:Embryonic and Fetal Development / Q000502:physiology; D005123:Eye / Q000196:embryology; D015870:Gene Expression / Q000502:physiology*; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D051379:Mice / Q000196:embryology; D008969:Molecular Sequence Data; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D036224:Receptor, EphB4; D036081:Receptors, Eph Family; D012160:Retina / Q000196:embryology*; D013477:Superior Colliculi / Q000196:embryology*; D014157:Transcription Factors; D014795:Visual Pathways / Q000196:embryology*; D000099260:Empty Spiracles Homeobox Proteins
D030161:Avian Proteins; D018398:Homeodomain Proteins; D020794:Receptor Protein-Tyrosine Kinases; D036224:Receptor, EphB4; D036081:Receptors, Eph Family; D014157:Transcription Factors; D000099260:Empty Spiracles Homeobox Proteins; C402296:Vax protein, chicken; C120595:Vax2 protein, mouse