About: Ciona is a research topic. Over the lifetime, 644 publications have been published within this topic receiving 22825 citations.
Papers published on a yearly basis
United States Department of Energy1, Kyoto University2, Marine Biological Laboratory3, University of Queensland4, Stanford University5, University of California, Berkeley6, McGill University7, National Institute of Genetics8, Aix-Marseille University9, Dalhousie University10, University of Tokyo11, Tokyo Metropolitan University12, Tohoku University13, University of South Florida14, Hokkaido University15, Stazione Zoologica Anton Dohrn16, IBM17, University of Maryland, College Park18, University of California, San Francisco19, University of Edinburgh20, Oak Ridge National Laboratory21, Los Alamos National Laboratory22
TL;DR: A draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis, is generated, suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development.
Abstract: The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis. The Ciona genome contains approximately 16,000 protein-coding genes, similar to the number in other invertebrates, but only half that found in vertebrates. Vertebrate gene families are typically found in simplified form in Ciona, suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development. The ascidian genome has also acquired a number of lineage-specific innovations, including a group of genes engaged in cellulose metabolism that are related to those in bacteria and fungi.
TL;DR: In this paper, a voltage-sensor-containing phosphatase (Ci-VSP) was proposed, which displays channel-like gating currents and directly translates changes in membrane potential into the turnover of phosphoinositides.
Abstract: Changes in membrane potential affect ion channels and transporters, which then alter intracellular chemical conditions. Other signalling pathways coupled to membrane potential have been suggested1,2,3 but their underlying mechanisms are unknown. Here we describe a novel protein from the ascidian Ciona intestinalis that has a transmembrane voltage-sensing domain homologous to the S1–S4 segments of voltage-gated channels and a cytoplasmic domain similar to phosphatase and tensin homologue. This protein, named C. intestinalis voltage-sensor-containing phosphatase (Ci-VSP), displays channel-like ‘gating’ currents and directly translates changes in membrane potential into the turnover of phosphoinositides. The activity of the phosphoinositide phosphatase in Ci-VSP is tuned within a physiological range of membrane potential. Immunocytochemical studies show that Ci-VSP is expressed in Ciona sperm tail membranes, indicating a possible role in sperm function or morphology. Our data demonstrate that voltage sensing can function beyond channel proteins and thus more ubiquitously than previously realized.
TL;DR: Evidence is presented that the embryo of the ascidian, Ciona intestinalis, is an easily manipulated system for investigating the establishment of basic chordate tissues and organs, thereby raising the possibility that the Notch signaling pathway plays a role in notochord differentiation.
Abstract: We present evidence that the embryo of the ascidian, Ciona intestinalis, is an easily manipulated system for investigating the establishment of basic chordate tissues and organs. Ciona has a small genome, and simple, well-defined embyronic lineages. Here, we examine the regulatory mechanisms underlying the differentiation of the notochord. Particular efforts center on the regulation of a notochord-specific Ciona Brachyury gene (Ci-Bra). An electroporation method was devised for the efficient incorporation of transgenic DNA into Ciona embryos. This method permitted the identification of a minimal, 434 bp enhancer from the Ci-Bra promoter region that mediates the notochord-restricted expression of both GFP and lacZ reporter genes. This enhancer contains a negative control region that excludes Ci-Bra expression from inappropriate embryonic lineages, including the trunk mesenchyme and tail muscles. Evidence is presented that the enhancer is activated by a regulatory element which is closely related to the recognition sequence of the Suppressor of Hairless transcription factor, thereby raising the possibility that the Notch signaling pathway plays a role in notochord differentiation. We discuss the implications of this analysis with regard to the evolutionary conservation of integrative enhancers, and the subdivision of the axial and paraxial mesoderm in vertebrates.
TL;DR: In this paper, a survey of the Ciona intestinalis genome was conducted to identify genes for Fox, ETS-domain transcription factors, nuclear receptors, and NFkappaB.
Abstract: A survey against the draft genome sequence and the cDNA/EST database of Ciona intestinalis identified a number of genes encoding transcription factors regulating a variety of processes including development. In the present study, we describe almost complete sets of genes for Fox, ETS-domain transcription factors, nuclear receptors, and NFkappaB as well as other factors regulating NFkappaB activity, with their phylogenetic nature. Vertebrate Fox transcription factors are currently delineated into 17 subfamilies: FoxA to FoxQ. The present survey yielded 29 genes of this family in the Ciona genome, 24 of which were Ciona orthologues of known Fox genes. In addition, we found 15 ETS genes, 17 nuclear receptor genes, and several NFkappaB signaling pathway genes in the Ciona genome. The number of Ciona genes in each family is much smaller than that of vertebrates, which represents a simplified feature of the ascidian genome. For example, humans have two NFkappaB genes, three Rel genes, and five NFAT genes, while Ciona has one gene for each family. The Ciona genome also contains smaller numbers of genes for the NFkappaB regulatory system, i.e. after the split of ascidians/vertebrates, vertebrates evolved a more complex NFkappaB system. The present results therefore provide molecular information for the investigation of complex developmental processes, and an insight into chordate evolution.
TL;DR: Deduced gene circuit diagrams describing the formation of larval tissues were computationally visualized and constitute a blueprint for the Ciona embryo and provide a foundation for understanding the evolutionary origins of the chordate body plan.
Abstract: Ciona is an emerging model system for elucidating gene networks in development. Comprehensive in situ hybridization assays have identified 76 regulatory genes with localized expression patterns in the early embryo, at the time when naive blastomeres are determined to follow specific cell fates. Systematic gene disruption assays provided more than 3000 combinations of gene expression profiles in mutant backgrounds. Deduced gene circuit diagrams describing the formation of larval tissues were computationally visualized. These diagrams constitute a blueprint for the Ciona embryo and provide a foundation for understanding the evolutionary origins of the chordate body plan.