The TINS Lecture. Understanding the roles of Otx1 and Otx2 in the control of brain morphogenesis.
The murine homologs of the orthodenticle (otd) gene of Drosophila, Otx1 and Otx2, have an important role in brain morphogenesis. Analysis of Otx1 and Otx2 null mice reveals that Otx1 is required primarily for corticogenesis and sense-organ development,while Otx2 is necessary for specification and maintenance of anterior neural plate as well as for proper gastrulation. Cross-phylum recoveries of Otx1 abnormalities by Drosophila otd, and vice versa, indicate that genetic functions required in mammalian-brain development evolved in a primitive ancestor of flies and mice. Knock-in mouse models in which Otx2 was replaced with Otx1, and vice versa, provide evidence that the existence of Otx1-/- and Otx2-/- divergent phenotypes largely reflects differences in expression patterns rather than in the biochemical activity of OTX1 and OTX2. In evolutionary terms, some of these findings lead us to hypothesize a fascinating and crucial role for Otx genes that contributes to the genetic program required for the specification of the development of the vertebrate head.
Acampora
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International Institute of Genetics and Biophysics, CNR, Naples, Italy.
Simeone
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D000818:Animals; D001921:Brain / Q000196:embryology*; D002540:Cerebral Cortex / Q000196:embryology; D002642:Chick Embryo; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics / Q000502:physiology; D004423:Ear / Q000002:abnormalities / Q000196:embryology; D004707:Endoderm / Q000378:metabolism; D019143:Evolution, Molecular; D005123:Eye / Q000196:embryology; D005124:Eye Abnormalities / Q000196:embryology / Q000235:genetics; D005326:Fetal Proteins / Q000502:physiology*; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D006257:Head / Q000002:abnormalities / Q000196:embryology; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051857:Otx Transcription Factors; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D012741:Sexual Maturation / Q000235:genetics; D013045:Species Specificity; D015534:Trans-Activators / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors
D029721:Drosophila Proteins; D005326:Fetal Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; C497656:Otx1 protein, mouse; C497660:Otx2 protein, mouse; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C093053:oc protein, Drosophila