Visual projection map specified by topographic expression of transcription factors in the retina.
Topographical maps of neuronal connectivity occur in various brain regions. In the visual system of birds, retinal ganglion-cell axons from the anterior retina connect to a posterior part of the optic tectum, and posterior retinal axons connect to the anterior part, thereby establishing a point-to-point projection map. The chemoaffinity theory predicts that the orderly retinotectal projection is generated by a topographical arrangement of molecules. We report here that we have found several genes topographically expressed along the nasotemporal (anterior-posterior) axis in the embryonic chicken retina. Among these, two transcriptional regulators, belonging to the winged-helix family are expressed in a mutually exclusive manner in either the nasal or temporal part of the retina. Misexpression of each factor causes misprojection on the tectum along the rostrocaudal axis, showing that topographical expression of these transcription factors controls formation of the retinotectal map.
Yuasa
J
J
Division of Molecular Neurobiology, National Institute for Basic Biology, and Department of Molecular Biomechanics, The Graduate University for Advanced Studies, Okaxaki, Japan.
Hirano
S
S
Yamagata
M
M
Noda
M
M
D000469:Alkaline Phosphatase / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001369:Axons; D001665:Binding Sites; D002645:Chickens; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D051858:Forkhead Transcription Factors; D005822:Genetic Vectors; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000196:embryology* / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D013477:Superior Colliculi / Q000196:embryology / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*; D014764:Viral Proteins; D014795:Visual Pathways / Q000196:embryology
D030161:Avian Proteins; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D009419:Nerve Tissue Proteins; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D014764:Viral Proteins; C490425:v-qin protein, Avian sarcoma virus 31; D000469:Alkaline Phosphatase