title: Analysis of opo cis-regulatory landscape uncovers Vsx2 requirement in early eye morphogenesis.
abstract: The self-organized morphogenesis of the vertebrate optic cup entails coupling the activation of the retinal gene regulatory network to the constriction-driven infolding of the retinal epithelium. Yet the genetic mechanisms underlying this coordination remain largely unexplored. Through phylogenetic footprinting and transgenesis in zebrafish, here we examine the cis-regulatory landscape of opo, an endocytosis regulator essential for eye morphogenesis. Among the different conserved enhancers identified, we isolate a single retina-specific element (H6_10137) and show that its activity depends on binding sites for the retinal determinant Vsx2. Gain- and loss-of-function experiments and ChIP analyses reveal that Vsx2 regulates opo expression through direct binding to this retinal enhancer. Furthermore, we show that vsx2 knockdown impairs the primary optic cup folding. These data support a model by which vsx2, operating through the effector gene opo, acts as a central transcriptional node that coordinates neural retina patterning and optic cup invagination in zebrafish.
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Ines
authors.initials: I
authors.lastname: Gago-Rodrigues
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Fernández-Miñán
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Letelier
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Naranjo
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Tena
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Gómez-Skarmeta
authors.affiliation: Centro Andaluz de Biologia del Desarrollo (CSIC/UPO/JA), 41013 Sevilla, Spain.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Martinez-Morales
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004742:Enhancer Elements, Genetic; D044127:Epigenesis, Genetic; D005123:Eye / Q000196:embryology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D055785:Gene Knockdown Techniques; D023281:Genomics; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D010802:Phylogeny; D011485:Protein Binding; D023302:Protein Footprinting; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055351:Retinal Neurons; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D029961:Zebrafish Proteins; C108000:vsx2 protein, zebrafish