The nervous systems of Cnidarians

Grimmelikhuijzen, Cornelis J.P.; Westfall, Jane A.

doi:10.1007/978-3-0348-9219-3_2

Cited by 107 publications

(67 citation statements)

References 71 publications

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“…NvNetrin is expressed in the same longitudinal stripe of body wall where several Hox genes are expressed. The circumpharangeal expression of N. vectensis homologs of genes such as NvNetrin, NvGremlin, NvNotch1, NvNotch2, and NvDelta (H.M., D.Q.M., and M.Q.M., unpublished work), correspond to the location of the nerve ring surrounding the mouth of cnidarians (68). This circumblastoporal concentration of nerves has been suggested to represent a precursor to the bilaterian CNS (69).…”

Section: Discussion Evolutionary Predecessor Of the D-v Axis?mentioning

confidence: 88%

Molecular evidence for deep evolutionary roots of bilaterality in animal development

Matus

Pang

Marlow

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

209

164

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Nearly all metazoans show signs of bilaterality, yet it is believed the bilaterians arose from radially symmetric forms hundreds of millions of years ago. Cnidarians (corals, sea anemones, and ''jellyfish'') diverged from other animals before the radiation of the Bilateria. They are diploblastic and are often characterized as being radially symmetrical around their longitudinal (oral-aboral) axis. We have studied the deployment of orthologs of a number of family members of developmental regulatory genes that are expressed asymmetrically during bilaterian embryogenesis from the sea anemone, Nematostella vectensis. The secreted TGF-␤ genes Nv-dpp, Nv-BMP5-8, six TGF-␤ antagonists (NvChordin, NvNoggin1, NvNoggin2, NvGremlin, NvFollistatin, and NvFollistatin-like), the homeodomain proteins NvGoosecoid (NvGsc) and NvGbx, and the secreted guidance factor, NvNetrin, were studied. NvDpp, NvChordin, NvNoggin1, NvGsc, and NvNetrin are expressed asymmetrically along the axis perpendicular to the oral-aboral axis, the directive axis. Furthermore, NvGbx, and NvChordin are expressed in restricted domains on the left and right sides of the body, suggesting that the directive axis is homologous with the bilaterian dorsal-ventral axis. The asymmetric expression of NvNoggin1 and NvGsc appear to be maintained by the canonical Wnt signaling pathway. The asymmetric expression of NvNoggin1, NvNetrin, and Hox orthologs NvAnthox7, NvAnthox8, NvAnthox1a, and NvAnthox6, in conjunction with the observation that NvNoggin1 is able to induce a secondary axis in Xenopus embryos argues that N. vectensis could possess antecedents of the organization of the bilaterian central nervous system.

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Section: Discussion Evolutionary Predecessor Of the D-v Axis?mentioning

confidence: 88%

Molecular evidence for deep evolutionary roots of bilaterality in animal development

Matus

Pang

Marlow

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

209

164

View full text Add to dashboard Cite

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“…In fact, cnidarian nervous systems are strongly peptidergic Grimmelikhuijzen and Westfall (1995), which is likely a major difference with bilaterian nervous systems. All together, these structural, biochemical, electrophysiological and molecular data support the view according to which this "simple" cnidarian nervous system exhibits a rather sophisticated organization, with strikingly evolutionarily-conserved properties.…”

Section: Figmentioning

confidence: 99%

“…Interestingly, neurons are organized as a nerve net, which can be visualised thanks to neuron-specific immunostaining: this nerve net is not uniform and distinct subsets of neurons with specific spatial distribution could be identified Grimmelikhuijzen et al (1989), Koizumi et al (1990). For example, the RFamide-expressing neurons are clearly more abundant in the hydra head and foot regions, while almost absent in the central part of the body column Grimmelikhuijzen and Westfall (1995). In addition to the nerve net, a dense anatomical structure, named the nerve ring was identified at the base of tentacles of some hydra species Koizumi et al (1992).…”

Section: Introductionmentioning

confidence: 99%

Neuronal evolution: analysis of regulatory genes in a first-evolved nervous system, the hydra nervous system

2004

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Cnidarians represent the first animal phylum with an organized nervous system and a complex active behavior. The hydra nervous system is formed of sensory-motoneurons, ganglia neurons and mechanoreceptor cells named nematocytes, which all differentiate from a common stem cell. The neurons are organized as a nerve net and a subset of neurons participate in a more complex structure, the nerve ring that was identified in most cnidarian species at the base of the tentacles. In order to better understand the genetic control of this neuronal network, we analysed the expression of evolutionarily-conserved regulatory genes in the hydra nervous system. The PRD-CLASS homeogene, prdl-b, and the nuclear orphan receptor, hyCOUP-TF, are expressed at strong levels in proliferating nematoblasts, a lineage where they were found repressed during patterning and morphogenesis, and at low levels in distinct subsets of neurons. Interestingly, PRD-CLASS homeobox and COUP-TF genes are also expressed during neurogenesis in bilaterians, suggesting that mechanoreceptor and neuronal cells derive from a common ancestral cell. Moreover, the PRD-CLASS homeobox gene prdl-a, the ANTP-CLASS homeobox gene msh, and the thrombospondin-related gene TSP1, which are expressed in distinct subset of neurons in the adult polyp, are also expressed during early budding and/or head regeneration. These data strengthen the fact that two distinct regulations, one for neurogenesis and another for patterning, already apply to these regulatory genes, a feature also identified in bilaterian related-genes.

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“…Lethal phenotypes associated with scully (D. melanogaster gene homologous to HSD17B10) mutants indicate an essential role of 17β-HSD 10 in β-oxidation of lipids in gonadal and neural tissues (Torroja et al, 1998). Given the generally high lipid content of cnidarian tissue and their relatively sophisticated nervous system (reviewed by Grimmelikhuijzen and Westfall, 1995;Kass-Simon and Pierobon, 2007;Tarrant, 2005), it would be of great interest to determine the roles of 17β-HSD 10 enzymes in cnidarian lipid metabolism and neural function. Two N. vectensis genes clustered with HSD17B12 and formed a sister group to HSD17B3.…”

Section: Discussionmentioning

confidence: 99%

Steroid metabolism in cnidarians: Insights from Nematostella vectensis

Tarrant

Reitzel

Blomquist

et al. 2009

Molecular and Cellular Endocrinology

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Cnidarians occupy a key evolutionary position as a sister group to bilaterian animals. While cnidarians contain a diverse complement of steroids, sterols, and other lipid metabolites, relatively little is known of the endogenous steroid metabolism or function in cnidarian tissues. Incubations of cnidarian tissues with steroid substrates have indicated the presence of steroid metabolizing enzymes, particularly enzymes with 17β-hydroxysteroid dehydrogenase (17β-HSD) activity. Through analysis of the genome of the starlet sea anemone, Nematostella vectensis, we identified a suite of genes in the short chain dehydrogenase/reductase (SDR) superfamily including homologs of genes that metabolize steroids in other animals. A more detailed analysis of Hsd17b4 revealed complex evolutionary relationships, apparent intron loss in several taxa, and predominantly adult expression in N. vectensis. Due to its ease of culture and available molecular tools N. vectensis is an excellent model for investigation of cnidarian steroid metabolism and gene function. KeywordsEvolution, hydroxysteroid dehydrogenase, short chain dehydrogenase/reductase Abbreviations CYP HSD AKR 3

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The nervous systems of Cnidarians

Cited by 107 publications

References 71 publications

Molecular evidence for deep evolutionary roots of bilaterality in animal development

Molecular evidence for deep evolutionary roots of bilaterality in animal development

Neuronal evolution: analysis of regulatory genes in a first-evolved nervous system, the hydra nervous system

Steroid metabolism in cnidarians: Insights from Nematostella vectensis

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