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Ulrich Technau - One of the best experts on this subject based on the ideXlab platform.
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gastrulation and germ layer formation in the sea anemone Nematostella Vectensis and other cnidarians
Mechanisms of Development, 2020Co-Authors: Ulrich TechnauAbstract:Abstract Among the basally branching metazoans, cnidarians display well-defined gastrulation processes leading to a diploblastic body plan, consisting of an endodermal and an ectodermal cell layer. As the outgroup to all Bilateria, cnidarians are an interesting group to investigate ancestral developmental mechanisms. Interestingly, all known gastrulation mechanisms known in Bilateria are already found in different species of Cnidaria. Here I review the morphogenetic processes found in different Cnidaria and focus on the investigation of the cellular and molecular mechanisms in the sea anemone Nematostella Vectensis, which has been a major model organism among cnidarians for evolutionary developmental biology. Many of the genes involved in germ layer specification and morphogenetic processes in Bilateria are also found active during gastrulation of Nematostella and other cnidarians, suggesting an ancestral role of this process. The molecular analyses indicate a tight link between gastrulation and axis patterning processes by Wnt and FGF signaling. Interestingly, the endodermal layer displays many features of the mesodermal layer in Bilateria, while the pharyngeal ectoderm has an endodermal expression profile. Comparative analyses as well as experimental studies using embryonic aggregates suggest that minor differences in the gene regulatory networks allow the embryo to transition relatively easily from one mode of gastrulation to another.
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Generating Transgenic Reporter Lines for Studying Nervous System Development in the Cnidarian Nematostella Vectensis.
Methods in molecular biology (Clifton N.J.), 2019Co-Authors: Fabian Rentzsch, Eduard Renfer, Ulrich TechnauAbstract:Neurons often display complex morphologies with long and fine processes that can be difficult to visualize, in particular in living animals. Transgenic reporter lines in which fluorescent proteins are expressed in defined populations of neurons are important tools that can overcome these difficulties. By using membrane-attached fluorescent proteins, such reporter transgenes can identify the complete outline of subsets of neurons or they can highlight the subcellular localization of fusion proteins, for example at pre- or postsynaptic sites. The relative stability of fluorescent proteins furthermore allows the tracing of the progeny of cells over time and can therefore provide information about potential roles of the gene whose regulatory elements are controlling the expression of the fluorescent protein. Here we describe the generation of transgenic reporter lines in the sea anemone Nematostella Vectensis, a cnidarian model organism for studying the evolution of developmental processes. We also provide an overview of existing transgenic Nematostella lines that have been used to study conserved and derived aspects of nervous system development.
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A cadherin switch marks germ layer formation in the diploblastic sea anemone Nematostella Vectensis.
Development, 2019Co-Authors: Ekaterina Pukhlyakova, A. O. Kirillova, Yulia Kraus, Bob Zimmermann, Ulrich TechnauAbstract:Morphogenesis is a shape-building process during development of multicellular organisms. During this process the establishment and modulation of cell-cell contacts play an important role. Cadherins, the major cell adhesion molecules, form adherens junctions connecting epithelial cells. Numerous studies in Bilateria have shown that cadherins are associated with the regulation of cell differentiation, cell shape changes, cell migration and tissue morphogenesis. To date, the role of Cadherins in non-bilaterians is unknown. Here, we study the expression and the function of two paralogous classical cadherins, cadherin1 and cadherin3, in the diploblastic animal, the sea anemone Nematostella Vectensis. We show that a cadherin switch is accompanying the formation of germ layers. Using specific antibodies, we show that both cadherins are localized to adherens junctions at apical and basal positions in ectoderm and endoderm. During gastrulation, partial EMT of endodermal cells is marked by a step-wise down-regulation of cadherin3 and up-regulation of cadherin1. Knockdown experiments show that both cadherins are required for maintenance of tissue integrity and tissue morphogenesis. Thus, both sea anemones and bilaterians use independently duplicated cadherins combinatorially for tissue morphogenesis and germ layer differentiation.
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cadherin switch marks germ layer formation in the diploblastic sea anemone Nematostella Vectensis
bioRxiv, 2018Co-Authors: Ekaterina Pukhlyakova, A. O. Kirillova, Yulia Kraus, Ulrich TechnauAbstract:Morphogenesis is a shape-building process during development of multicellular organisms. During this process the establishment and modulation of cell-cell contacts play an important role. Cadherins, the major cell adhesion molecules, form adherens junctions connecting epithelial cells. Numerous studies in Bilateria have shown that cadherins are associated with the regulation of cell differentiation, cell shape changes, cell migration and tissue morphogenesis. To date, the role of Cadherins in non-bilaterians is unknown. Here, we study the expression and the function of two paralogous classical cadherins, cadherin1 and cadherin3, in the diploblastic animal, the sea anemone Nematostella Vectensis. We show that a cadherin switch is accompanying the formation of germ layers. Using specific antibodies, we show that both cadherins are localized to adherens junctions at apical and basal positions in ectoderm and endoderm. During gastrulation, partial EMT of endodermal cells is marked by a step-wise downregulation of cadherin3 and upregulation of cadherin1. Knockdown experiments show that both cadherins are required for maintenance of tissue integrity and tissue morphogenesis. This demonstrates that cnidarians convergently use cadherins to differentially control morphogenetic events during development.
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Characterization of the piRNA pathway during development of the sea anemone Nematostella Vectensis
RNA biology, 2017Co-Authors: Daniela Praher, Bob Zimmermann, Yehu Moran, Yaara Y. Columbus-shenkar, Grigory Genikhovich, Vengamanaidu Modepalli, Reuven Aharoni, Ulrich TechnauAbstract:PIWI-interacting RNAs (piRNAs) and associated proteins comprise a conserved pathway for silencing transposons in metazoan germlines. piRNA pathway components are also expressed in multipotent somatic stem cells in various organisms. piRNA functions have been extensively explored in bilaterian model systems, however, comprehensive studies in non-bilaterian phyla remain limited. Here we investigate the piRNA pathway during the development of Nematostella Vectensis, a well-established model system belonging to Cnidaria, the sister group to Bilateria. To date, no population of somatic stem cells has been identified in this organism, despite its long life-span and regenerative capacities that require a constant cell-renewal. We show that Nematostella piRNA pathway components are broadly expressed in early developmental stages, while piRNAs themselves show differential expression, suggesting specific developmental roles of distinct piRNA families. In adults, piRNA associated proteins are enriched in the germline but also expressed in somatic cells, indicating putative stem cell properties. Furthermore, we provide experimental evidence that Nematostella piRNAs cleave transposable elements as well as protein-coding genes. Our results demonstrate that somatic expression of piRNA associated proteins as well as the roles of piRNAs in transposon repression and gene regulation are likely ancestral features that evolved before the split between Cnidaria and Bilateria.
John R Finnerty - One of the best experts on this subject based on the ideXlab platform.
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Physiological and developmental responses to temperature by the sea anemone Nematostella Vectensis
Marine Ecology Progress Series, 2013Co-Authors: Adam M Reitzel, Ann M Tarrant, Tim Chu, Sara K. Edquist, Caitlyn Genovese, Caitlin Church, John R FinnertyAbstract:Environmental temperature and an organism's ability to respond to it are critical determinants of the geographic distribution of species. Nematostella Vectensis is a burrowing sea anemone that inhabits estuaries along the Atlantic coast of North America from Nova Scotia (45° N) to Georgia (31° N). Like other estuarine species, N. Vectensis is exposed to large daily (>20°C) and seasonal (>25°C) fluctuations in temperature, requiring wide temperature tolerances. At the same time, the natural distribution of this species spans a pronounced thermal cline, which may promote the evolution of different temperature optima and tolerances in populations. We tested the thermal tolerance of N. Vectensis adult and developmental stages, which showed all life cycle stages had critical temperatures within 1°C (lethal temperature 39.5 to 40.5°C). When tem- perature tolerance values were compared with recorded field data, N. Vectensis is living in envi- ronments very close to their physiological limit. We utilized common garden experiments (13, 21, and 29°C) to test for temperature-specific growth and regeneration rates in N. Vectensis from dif- ferent portions of this species' range. Temperature had a significant effect on growth and regen- eration rate in all clonal lines, with a significant negative relationship between latitude of origin and growth rate at 29°C. Individuals from higher latitudes did not exhibit higher growth rates at cooler temperatures. Together, our results show a combination of broad thermal tolerances for developmental and adult stages and evidence for local adaptation to higher temperatures in pop- ulations living in lower latitude locations that would be physiologically compromised with future warming.
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A report from the second Nematostella Vectensis research conference
Development Genes and Evolution, 2013Co-Authors: Thomas D Gilmore, Ann M Tarrant, John R FinnertyAbstract:This report summarizes information discussed at the second Nematostella Vectensis research conference, which took place on August 27, 2012 in Boston, MA, USA. The startlet sea anemone Nematostella is emerging as one of leading model organisms among cnidarians, in part because of the extensive genome and transcriptome resources that are becoming available for Nematostella , which were the focus of several presentations. In addition, research was presented on the use of Nematostella in developmental, regeneration, signal transduction, host–symbiont, and gene–environment interaction studies.
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isolation of dna rna and protein from the starlet sea anemone Nematostella Vectensis
Nature Protocols, 2013Co-Authors: Derek J Stefanik, Francis S Wolenski, Thomas D Gilmore, Lauren E Friedman, John R FinnertyAbstract:Among marine invertebrates, the starlet sea anemone Nematostella Vectensis has emerged as an important laboratory model system. One advantage of working with this species relative to many other marine invertebrates is the ease of isolating relatively pure DNA, RNA and protein. Nematostella can be raised at high densities, under clean culture conditions, and it lacks integumentary or skeletal structures that can impede the recovery of DNA, RNA or protein. Here we describe methods used in our lab to isolate DNA, RNA and protein from Nematostella embryos, larvae and adults. The methods described here are less expensive than commercial kits and are more easily scalable to larger tissue amounts. Preparation of DNA can be completed in ∼7 h, RNA preparation in ∼1.5 h and protein preparation in ∼1 h.
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Collecting, rearing, spawning and inducing regeneration of the starlet sea anemone, Nematostella Vectensis
Nature Protocols, 2013Co-Authors: Derek J Stefanik, Lauren E Friedman, John R FinnertyAbstract:Over the past 20 years, the starlet sea anemone, Nematostella Vectensis , a small estuarine animal, has emerged as a powerful model system for field and laboratory studies of development, evolution, genomics, molecular biology and toxicology. Here we describe how to collect Nematostella , culture it through its entire sexual life cycle and induce regeneration for the production of clonal stocks. In less than 1 h at a suitable field site, a researcher on foot can collect hundreds of individual anemones. In a few months, it is possible to establish a laboratory colony that will be reliable in generating hundreds or thousands of fertilized eggs on a roughly weekly schedule. By inducing regeneration roughly every 2 weeks, in less than 6 months, one can establish a clonal stock consisting of hundreds of genetically identical anemones. These results can be achieved very inexpensively and without specialized equipment.
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characterizing the spatiotemporal expression of rnas and proteins in the starlet sea anemone Nematostella Vectensis
Nature Protocols, 2013Co-Authors: Francis S Wolenski, Michael J Layden, Thomas D Gilmore, Mark Q Martindale, John R FinnertyAbstract:In an effort to reconstruct the early evolution of animal genes and proteins, there is an increasing focus on basal animal lineages such as sponges, cnidarians, ctenophores and placozoans. Among the basal animals, the starlet sea anemone Nematostella Vectensis (phylum Cnidaria) has emerged as a leading laboratory model organism partly because it is well suited to experimental techniques for monitoring and manipulating gene expression. Here we describe protocols adapted for use in Nematostella to characterize the expression of RNAs by in situ hybridization using either chromogenic or fluorescence immunohistochemistry (∼1 week), as well as to characterize protein expression by whole-mount immunofluorescence (∼3 d). We also provide a protocol for labeling cnidocytes (∼3 h), the phylum-specific sensory-effector cell type that performs a variety of functions in cnidarians, including the delivery of their venomous sting.
Mark Q Martindale - One of the best experts on this subject based on the ideXlab platform.
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Par system components are asymmetrically localized in ectodermal epithelia, but not during early development in the sea anemone Nematostella Vectensis
EvoDevo, 2015Co-Authors: Miguel Salinas-saavedra, Casey W. Dunn, Thomas Q Stephenson, Mark Q MartindaleAbstract:Background The evolutionary origins of cell polarity in metazoan embryos are unclear. In most bilaterian animals, embryonic and cell polarity are set up during embryogenesis with the same molecules being utilized to regulate tissue polarity at different life stages. Atypical protein kinase C (aPKC), lethal giant larvae (Lgl), and Partitioning-defective (Par) proteins are conserved components of cellular polarization, and their role in establishing embryonic asymmetry and tissue polarity have been widely studied in model bilaterian groups. However, the deployment and role of these proteins in animals outside Bilateria has not been studied. We address this by characterizing the localization of different components of the Par system during early development of the sea anemone Nematostella Vectensis, a member of the clade Cnidaria, the sister group to bilaterian animals.
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microinjection of mrna or morpholinos for reverse genetic analysis in the starlet sea anemone Nematostella Vectensis
Nature Protocols, 2013Co-Authors: Michael J Layden, Eric Röttinger, Francis S Wolenski, Thomas D Gilmore, Mark Q MartindaleAbstract:Microinjection of mRNA or morpholinos for reverse genetic analysis in the starlet sea anemone, Nematostella Vectensis
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characterizing the spatiotemporal expression of rnas and proteins in the starlet sea anemone Nematostella Vectensis
Nature Protocols, 2013Co-Authors: Francis S Wolenski, Michael J Layden, Thomas D Gilmore, Mark Q Martindale, John R FinnertyAbstract:In an effort to reconstruct the early evolution of animal genes and proteins, there is an increasing focus on basal animal lineages such as sponges, cnidarians, ctenophores and placozoans. Among the basal animals, the starlet sea anemone Nematostella Vectensis (phylum Cnidaria) has emerged as a leading laboratory model organism partly because it is well suited to experimental techniques for monitoring and manipulating gene expression. Here we describe protocols adapted for use in Nematostella to characterize the expression of RNAs by in situ hybridization using either chromogenic or fluorescence immunohistochemistry (∼1 week), as well as to characterize protein expression by whole-mount immunofluorescence (∼3 d). We also provide a protocol for labeling cnidocytes (∼3 h), the phylum-specific sensory-effector cell type that performs a variety of functions in cnidarians, including the delivery of their venomous sting.
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Cell proliferation is necessary for the regeneration of oral structures in the anthozoan cnidarian Nematostella Vectensis
BMC developmental biology, 2012Co-Authors: Yale J. Passamaneck, Mark Q MartindaleAbstract:Background The contribution of cell proliferation to regeneration varies greatly between different metazoan models. Planarians rely on pluripotent neoblasts and amphibian limb regeneration depends upon formation of a proliferative blastema, while regeneration in Hydra can occur in the absence of cell proliferation. Recently, the cnidarian Nematostella Vectensis has shown potential as a model for studies of regeneration because of the ability to conduct comparative studies of patterning during embryonic development, asexual reproduction, and regeneration. The present study investigates the pattern of cell proliferation during the regeneration of oral structures and the role of cell proliferation in this process.
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Functional roles of Notch signaling in the cnidarian Nematostella Vectensis
Developmental biology, 2011Co-Authors: Heather Q. Marlow, Eric Roettinger, Michiel Boekhout, Mark Q MartindaleAbstract:Notch signaling is among the oldest of known Metazoan signaling pathways and is used in a multitude of developmental contexts to effect cellular differentiation, specification and the maintenance of stem cell state. Here we report the isolation and expression of the canonical Notch signaling pathway in the early branching metazoan Nematostella Vectensis (Anthozoa, Cnidaria) during embryonic and larval development. We have used pharmacological treatment, morpholino knockdown, and dominant negative misexpression experiments to demonstrate that Notch signaling acts to mediate cnidogenesis, the development of cnidarian-specific neural effecter cells. Notch signaling often results in the transcriptional activation of NvHes genes, a conserved family of bHLH transcription factors. A loss of Notch signaling through use of pharmacological inhibition or knock-down of the Notch effecter gene Suppressor of Hairless Su(H) similarly results in a loss of cnidocyte cell fate. We also provide evidence that Notch signaling is responsible for certain aspects of neurogenesis in developing N. Vectensis planula in which disruption of Notch cleavage via the pharmacological agent DAPT results in increased expression of neural marker genes in vivo. This data suggests that Notch signaling acting on components of the developing nervous system is an ancient role of this pathway. The shared requirement of Notch signaling for the development of both cnidocytes and neurons further supports the hypothesis that cnidocytes and neurons share common origins as multifunctional sensory-effecter cells.
Eric Röttinger - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomic Analysis in the Sea Anemone Nematostella Vectensis.
Methods in Molecular Biology, 2020Co-Authors: Jacob F. Warner, Eric RöttingerAbstract:The sea anemone Nematostella Vectensis is an emerging research model to study embryonic development and regeneration at the molecular and global transcriptomic level. Transcriptomics analysis is now routinely used to detect differential expression at the genome level. Here we present the latest procedures for isolating high-quality RNA required for next generation sequencing, as well as methods and resources for quantifying transcriptomic data.
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Experimental Tools to Study Regeneration in the Sea Anemone Nematostella Vectensis.
Methods in molecular biology (Clifton N.J.), 2020Co-Authors: Aldine R. Amiel, Eric RöttingerAbstract:Animal regeneration is a biological process leading to the reformation of injured or lost tissues/body parts. One of the most fascinating regenerative phenomena is the so-called whole-body regeneration, leading to the reformation of fully functional organisms within days after bisection. The sea anemone Nematostella Vectensis is currently emerging as novel whole-body regeneration model. Here we describe the methods of inducing the regenerative process in this cnidarian as well as the fixation and staining protocols for morphological, molecular, and cellular analysis.
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nvertx a gene expression database to compare embryogenesis and regeneration in the sea anemone Nematostella Vectensis
bioRxiv, 2018Co-Authors: Jacob F. Warner, Aldine R. Amiel, Hereroa Johnston, Karine Nedoncelle, Vincent Guerlais, Eric RöttingerAbstract:For more than a century researchers have been comparing embryogenesis and regeneration hoping that lessons learned from embryonic development will unlock hidden regenerative potential. This problem has historically been a difficult one to investigate since the best regenerative model systems are poor embryonic models and vice versa. Recently however, the comparison of embryogenesis and regeneration has seen renewed interest as emerging models including the sea anemone Nematostella Vectensis have allowed researchers to investigate these processes in the same organism. This interest has been further fueled by the advent of high-throughput transcriptomic analyses that provide virtual mountains of data. Unfortunately much of this data remains in raw unanalyzed formats that are difficult to access or browse. Here we present Nematostella Vectensis Embryogenesis and Regeneration Transcriptomics - NvERTx, the first platform for comparing gene expression during embryogenesis and regeneration. NvERTx is comprised of close to 50 RNAseq datasets spanning embryogenesis and regeneration in Nematostella. These data were used to perform a robust de novo transcriptome assembly which users can search, BLAST and plot expression of multiple genes during these two developmental processes. The site is also home to the results of gene clustering analyses, to further mine the data and identify groups of co-expressed genes. The site can be accessed at http://nvertx.kahikai.org.
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nvertx a gene expression database to compare embryogenesis and regeneration in the sea anemone Nematostella Vectensis
Development, 2018Co-Authors: Jacob F. Warner, Aldine R. Amiel, Hereroa Johnston, Karine Nedoncelle, Vincent Guerlais, Eric RöttingerAbstract:For over a century, researchers have been comparing embryogenesis and regeneration hoping that lessons learned from embryonic development will unlock hidden regenerative potential. This problem has historically been a difficult one to investigate because the best regenerative model systems are poor embryonic models and vice versa. Recently, however, there has been renewed interest in this question, as emerging models have allowed researchers to investigate these processes in the same organism. This interest has been further fueled by the advent of high-throughput transcriptomic analyses that provide virtual mountains of data. Here, we present Nematostella Vectensis Embryogenesis and Regeneration Transcriptomics (NvERTx), a platform for comparing gene expression during embryogenesis and regeneration. NvERTx consists of close to 50 transcriptomic data sets spanning embryogenesis and regeneration in Nematostella These data were used to perform a robust de novo transcriptome assembly, with which users can search, conduct BLAST analyses, and plot the expression of multiple genes during these two developmental processes. The site is also home to the results of gene clustering analyses, to further mine the data and identify groups of co-expressed genes. The site can be accessed at http://nvertx.kahikai.org.
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Characterization of Morphological and Cellular Events Underlying Oral Regeneration in the Sea Anemone, Nematostella Vectensis
International Journal of Molecular Sciences, 2015Co-Authors: Aldine Amiel, Hereroa Johnston, Karine Nedoncelle, Jacob Warner, Solène Ferreira, Eric RöttingerAbstract:Cnidarians, the extant sister group to bilateria, are well known for their impressive regenerative capacity. The sea anemone Nematostella Vectensis is a well-established system for the study of development and evolution that is receiving increased attention for its regenerative capacity. Nematostella is able to regrow missing body parts within five to six days after its bisection, yet studies describing the morphological, cellular, and molecular events underlying this process are sparse and very heterogeneous in their experimental approaches. In this study, we lay down the basic framework to study oral regeneration in Nematostella Vectensis. Using various imaging and staining techniques we characterize in detail the morphological, cellular, and global molecular events that define specific landmarks of this process. Furthermore, we describe in vivo assays to evaluate wound healing success and the initiation of pharynx reformation. Using our described landmarks for regeneration and in vivo assays, we analyze the effects of perturbing either transcription or cellular proliferation on the regenerative process. Interestingly, neither one of these experimental perturbations has major effects on wound closure, although they slightly delay or partially block it. We further show that while the inhibition of transcription blocks regeneration in a very early step, inhibiting cellular proliferation only affects later events such as pharynx reformation and tentacle elongation.
Adam M Reitzel - One of the best experts on this subject based on the ideXlab platform.
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Dataset of Nematostella Vectensis Hsp70 isoform interactomes upon heat shock
Data in brief, 2019Co-Authors: Laura E. Knighton, Adam M Reitzel, Nitika, Donald Wolfgeher, Andrew W. TrumanAbstract:Abstract Nematostella Vectensis is an estuarine sea anemone that has emerged as a model species to characterize molecular responses to physiological stressors due to its exposure to diverse, extreme abiotic conditions. In marine cnidarians, Hsp70 proteins can be effective biomarkers to determine mechanisms of physiological acclimation and evolutionary adaptations to environmental stress: a pressing issue as concerns about climate change grow. Here we show the results of affinity purification mass spectrometry of three Nematostella Vectensis Hsp70 isoforms, NvHsp70A, B and D when expressed in untreated and heat shocked yeast cells lacking their native Hsp70s. We identified a total of 1031 interactors for the three NvHsp70 isoforms, 549 or which were shared. NvHsp70 isoform interactions altered substantially under heat stress with 17% of NvHsp70A, 51% of NvHsp70B and 20% of NvHsp70D interactions increasing after exposure to 39 °C for 2 hours. For further interpretation of the data presented in this article, please see the research article “Dynamic remodeling of the interactomes of Nematostella Vectensis Hsp70 isoforms under heat shock”.
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Dynamic remodeling of the interactomes of Nematostella Vectensis Hsp70 isoforms under heat shock
Journal of proteomics, 2019Co-Authors: Laura E. Knighton, Adam M Reitzel, Nitika, Donald Wolfgeher, Shawn J. Waller, Owen Strom, Andrew W. TrumanAbstract:Abstract Heat shock protein 70s (Hsp70s) are a highly conserved class of molecular chaperones that fold a large proportion of the proteome. Nematostella Vectensis (Nv) is an estuarine sea anemone that has emerged as a model species to characterize molecular responses to physiological stressors due to its exposure to diverse, extreme abiotic conditions. Previous transcriptional data has shown dramatic differences among expression profiles of three NvHsp70 isoforms (NvHsp70A, B and D) under stress but it is unknown if, and to what extent, the client proteins for these chaperones differ. In order to determine client specificity, NvHsp70A, B and D were expressed in Saccharomyces cerevisiae budding yeast lacking native Hsp70 and interacting proteins for each Hsp70 were determined with mass spectrometry in yeast ambient and heat shock conditions. Our analyses showed Biological significance Although the Hsp70 family of molecular chaperones has been studied for >50 years, it is still not fully understood why organisms encode and express many highly-similar Hsp70 isoforms. The prevailing theory is that these isoforms have identical function, but are expressed under unique cellular conditions that include heat shock to cope with increased number of unfolded/misfolded proteins. The sea anemone Nematostella Vectensis encodes three Hsp70 isoforms A, B and D that when expressed in yeast demonstrate unique functionalities. This study provides the interactome of NvHsp70s A, B and D and demonstrates that Hsp70 isoforms, while highly similar in sequence, have unique co-chaperone and client interactors.
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Daily cycle in oxygen consumption by the sea anemone Nematostella Vectensis Stephenson
Biology open, 2016Co-Authors: Amy E. Maas, Adam M Reitzel, Ian T. Jones, Ann M TarrantAbstract:In bilaterian animals, the circadian clock is intimately involved in regulating energetic metabolism. Although cnidarians exhibit diel behavioral rhythms including cycles in locomotor activity, tentacle extension and spawning, daily cycles in cnidarian metabolism have not been described. To explore a possible circadian metabolic cycle, we maintained the anemone Nematostella Vectensis in a 12 h light/ dark cycle, a reversed light cycle, or in constant darkness. Oxygen consumption rates were measured at intervals using an optical oxygen meter. Respiration rates responded to entrainment with higher rates during light periods. During a second experiment with higher temporal resolution, respiration rates peaked late in the light period. The diel pattern could be detected after six days in constant darkness. Together, our results suggest that respiration rates in Nematostella exhibit a daily cycle that may be under circadian control and that the cycle in respiration rate is not driven by the previously described nocturnal increase in locomotor activity in this species.
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Response of bacterial colonization in Nematostella Vectensis to development, environment and biogeography.
Environmental microbiology, 2015Co-Authors: Benedikt M Mortzfeld, Ulrich Technau, Adam M Reitzel, Szymon Urbanski, Sven Künzel, Sebastian FrauneAbstract:Summary The establishment of host–bacterial colonization during development is a fundamental process influencing the fitness of many organisms, but the factors controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. The starlet sea anemone Nematostella Vectensis serves as a cnidarian model organism due to the availability of laboratory cultures and its high tolerance for broad ranges of salinity and temperature. Here, we show that the anemone's epithelia are colonized by diverse bacterial communities and that the composition of its microbiota is tightly coupled to host development. Environmental variations led to robust adjustments in the microbial composition while still maintaining the ontogenetic core signature. In addition, analysis of bacterial communities of Nematostella polyps from five different populations revealed a strong correlation between host biogeography and bacterial diversity despite years of laboratory culturing. These observed variations in fine-scale community composition following environmental change and for individuals from different geographic origins could represent the microbiome's contribution to host acclimation and potentially adaptation, respectively, and thereby contribute to the maintenance of homeostasis due to environmental changes.
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Physiological and developmental responses to temperature by the sea anemone Nematostella Vectensis
Marine Ecology Progress Series, 2013Co-Authors: Adam M Reitzel, Ann M Tarrant, Tim Chu, Sara K. Edquist, Caitlyn Genovese, Caitlin Church, John R FinnertyAbstract:Environmental temperature and an organism's ability to respond to it are critical determinants of the geographic distribution of species. Nematostella Vectensis is a burrowing sea anemone that inhabits estuaries along the Atlantic coast of North America from Nova Scotia (45° N) to Georgia (31° N). Like other estuarine species, N. Vectensis is exposed to large daily (>20°C) and seasonal (>25°C) fluctuations in temperature, requiring wide temperature tolerances. At the same time, the natural distribution of this species spans a pronounced thermal cline, which may promote the evolution of different temperature optima and tolerances in populations. We tested the thermal tolerance of N. Vectensis adult and developmental stages, which showed all life cycle stages had critical temperatures within 1°C (lethal temperature 39.5 to 40.5°C). When tem- perature tolerance values were compared with recorded field data, N. Vectensis is living in envi- ronments very close to their physiological limit. We utilized common garden experiments (13, 21, and 29°C) to test for temperature-specific growth and regeneration rates in N. Vectensis from dif- ferent portions of this species' range. Temperature had a significant effect on growth and regen- eration rate in all clonal lines, with a significant negative relationship between latitude of origin and growth rate at 29°C. Individuals from higher latitudes did not exhibit higher growth rates at cooler temperatures. Together, our results show a combination of broad thermal tolerances for developmental and adult stages and evidence for local adaptation to higher temperatures in pop- ulations living in lower latitude locations that would be physiologically compromised with future warming.
