title: Mutual repression between Gbx2 and Otx2 in sensory placodes reveals a general mechanism for ectodermal patterning.
abstract: In the vertebrate head, central and peripheral components of the sensory nervous system have different embryonic origins, the neural plate and sensory placodes. This raises the question of how they develop in register to form functional sense organs and sensory circuits. Here we show that mutual repression between the homeobox transcription factors Gbx2 and Otx2 patterns the placode territory by influencing regional identity and by segregating inner ear and trigeminal progenitors. Activation of Otx2 targets is necessary for anterior olfactory, lens and trigeminal character, while Gbx2 function is required for the formation of the posterior otic placode. Thus, like in the neural plate antagonistic interaction between Otx2 and Gbx2 establishes positional information thus providing a general mechanism for rostro-caudal patterning of the ectoderm. Our findings support the idea that the Otx/Gbx boundary has an ancient evolutionary origin to which different modules were recruited to specify cells of different fates.
authors.affiliation: Department of Craniofacial Development, King's College London, Guy's Campus, Tower Wing Floor 27, London SE1 9RT, UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Steventon
authors.forename: Roberto
authors.initials: R
authors.lastname: Mayor
authors.forename: Andrea
authors.initials: A
authors.lastname: Streit
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004475:Ectoderm / Q000196:embryology*; D018398:Homeodomain Proteins / Q000378:metabolism*; D009024:Morphogenesis; D051857:Otx Transcription Factors; D012679:Sense Organs / Q000196:embryology*; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins / Q000378:metabolism*
chemical_list: C513180:Gbx2 protein, Xenopus; D018398:Homeodomain Proteins; D051857:Otx Transcription Factors; C497661:Otx2 protein, Xenopus; D029867:Xenopus Proteins