title: Diverse ETS transcription factors mediate FGF signaling in the Ciona anterior neural plate.
abstract: The ascidian Ciona intestinalis is a marine invertebrate belonging to the sister group of the vertebrates, the tunicates. Its compact genome and simple, experimentally tractable embryos make Ciona well-suited for the study of cell-fate specification in chordates. Tunicate larvae possess a characteristic chordate body plan, and many developmental pathways are conserved between tunicates and vertebrates. Previous studies have shown that FGF signals are essential for neural induction and patterning at sequential steps of Ciona embryogenesis. Here we show that two different ETS family transcription factors, Ets1/2 and Elk1/3/4, have partially redundant activities in the anterior neural plate of gastrulating embryos. Whereas Ets1/2 promotes pigment cell formation in lateral lineages, both Ets1/2 and Elk1/3/4 are involved in the activation of Myt1L in medial lineages and the restriction of Six3/6 expression to the anterior-most regions of the neural tube. We also provide evidence that photoreceptor cells arise from posterior regions of the presumptive sensory vesicle, and do not depend on FGF signaling. Cells previously identified as photoreceptor progenitors instead form ependymal cells and neurons of the larval brain. Our results extend recent findings on FGF-dependent patterning of anterior-posterior compartments in the Ciona central nervous system.
authors.affiliation: Center for Integrative Genomics, Division of Genetics, Genomics and Development, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: T Blair
authors.initials: TB
authors.lastname: Gainous
authors.affiliation: Center for Integrative Genomics, Division of Genetics, Genomics and Development, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Eileen
authors.initials: E
authors.lastname: Wagner
authors.affiliation: Center for Integrative Genomics, Division of Genetics, Genomics and Development, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA. Electronic address: mlevine@berkeley.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Levine
mesh_terms: D000818:Animals; D019070:Cell Lineage / Q000502:physiology*; D002938:Ciona intestinalis / Q000196:embryology*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000502:physiology; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D018613:Microscopy, Confocal; D054258:Neural Plate / Q000502:physiology*; D050784:Proto-Oncogene Protein c-ets-1 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D050784:Proto-Oncogene Protein c-ets-1; D050807:ets-Domain Protein Elk-1; D005346:Fibroblast Growth Factors
keywords: Ciona intestinalis; ETS; FGF; Neural patterning