Project description:The basic helix-loop helix transcription factor Twist plays diverse roles in mesodermal development across bilaterians, but its function in cnidarians remains unclear. Here, we investigate the role of Twist in tentacle morphogenesis and tissue homeostasis in the sea anemone Nematostella vectensis. Using a CRISPR/Cas9 generated knockout, we show that twist mutants exhibit impaired secondary tentacle formation, reduced proliferation in budding tentacles, and absence of micronemes, structures that demarcate tentacle boundaries-suggesting defects in spatial patterning. We demonstrate that twist expression is regulated by Wnt, BMP, and Notch signalling but is independent of MAPK and Hedgehog pathways. Loss of Twist disrupts expression of mesodermal transcription factors paraxis and tbx15 and perturbs the TOR-FGF signalling feedback loop necessary for normal tentacle growth. Moreover, starting at juveniles, mutants develop neoplasm-like epithelial overgrowth with tentacle-like molecular and morphological profiles, indicating a role for Twist in maintaining tissue homeostasis at the oral pole. Together, our findings reveal that Twist integrates major signalling pathways to regulate secondary tentacle patterning and maintain spatial tissue organisation in the diploblastic Nematostella vectensis.
Project description:MicroRNAs of bilaterian animals undergo posttranscriptional modifications such as methylation, tailing and trimming that regulate miRNA stability and function. To gain insight on the evolution of miRNA posttranscriptional modification, we studied regulation of miRNA stability by methylation in the sea anemone Nematostella vectensis, a representative of Cnidaria, the sister group of Bilateria.
Project description:NvNcol3::mOrange2 is a stable transgenic line that labels cnidocytes(stinging cells) of the sea anemone Nematostella vectensis (Nakanishi et al., Development 2012). Two week old primary polyps were dissociated and the NvNcol3::mOrange2 positive and negative cells were enriched by FACS.
Project description:NvElav1::mOrange is a stable transgenic line that labels a large fraction of the nervous system of the sea anemone Nematostella vectensis (Nakanishi et al., Development 2012). Two week old primary polyps were dissociated and the NvElav1::mOrange positive cells were enriched by FACS.
Project description:The aim of this part of the wider project is to identify neuropeptide precursors, investigate cleavage sites on neuropeptide precursors and predict mature peptides in the sea anemone Nematostella vectensis. This was done to create a synthetic library of N. vectensis neuropeptides which were then used to test neuropeptide receptor candidates for activation by the different peptides.
Project description:We assessed genome-wide temporal transcript expression patterns in the sea anemone, Nematostella vectensis, in Great Sippewissett Marsh in Massachusetts, where anemones experienced a natural light cycle with intensity varying from 0-200 lum/ft2, daily temperature fluctuations of ~9C. We measured ‘in situ’ gene expression from recaptured anemones every hour from 0800 to 1700 and identified six time-dependent gene clusters, represented by several genes involved in metabolism, stress, and transcription-translation related functions.
Project description:While FGF mediated MEK/ERK signaling is required for apical tuft formation and metamorphosis in the sea anemone Nematostella vectensis (Rentzsch et al, 2008), nothing is known about the role of MEK/ERK signaling in inducing germ layers and cell types during early developmental stages. We therefore performed a genome wide expression array on UO126 (MEK inhibitor) treated blastula stages compared to DMSO treated control embryos and identified genes potentially involved in neurogenesis, germ layer specification and axial patterning.We performed transcriptional profiling of Nematostella vectensis blastula stages (24 hours post fertilisation @ 17C) using a custom made whole genome array (4x72K - A-MEXP-2380). DMSO treated wild-type embryos were compared to U0126 (MEK Inhibitor) treated embryos at the blastula stage.
Project description:Using the sea anemone Nematostella vectensis as a model for early branching metazoans, we show that CoREST is an animal-specific protein that assembles a conserved histone-modifying complex including Lsd1 and HDAC1/2. We further show that the Nematostella complex is similar in composition to vertebrates.
Project description:In mammals, the cGAS-cGAMP-STING pathway is crucial for sensing viral infection and initiating an anti-viral type I interferon response. cGAS and STING are highly conserved genes that originated in bacteria and are present in most animals. By contrast, interferons only emerged in vertebrates; thus, the function of STING in invertebrates is unclear. Here, we use the STING ligand 2'3'-cGAMP to activate immune responses in a model cnidarian invertebrate, the starlet sea anemone Nematostella vectensis. Using RNA-Seq, we found that 2'3'-cGAMP induces robust transcription of both anti-viral and anti-bacterial genes, including the conserved transcription factor NF-κB. Knockdown experiments identified a role for NF-κB in specifically inducing anti-bacterial genes downstream of 2'3'-cGAMP, and some of these genes were also found to be induced during Pseudomonas aeruginosa infection. Furthermore, we characterized the protein product of one of the putative anti-bacterial genes, the N. vectensis homolog of Dae4, and found that it has conserved anti-bacterial activity. This work describes an unexpected role of a cGAMP sensing pathway in anti-bacterial immunity and suggests that a broad transcriptional response is an evolutionarily ancestral output of 2'3'-cGAMP signaling in animals.
Project description:Cnidarians, including corals, sea anemones, and jellyfish, possess specialized stinging cells called cnidocytes that function in prey capture and defense. These cells represent a striking evolutionary innovation and include distinct types such as venom injecting nematocytes and mechanically acting spirocytes. While their biomechanics and transcriptional regulation have been studied extensively, little is known about their epigenetic regulation. Here, we combined epigenetic profiling with RNA sequencing in the sea anemone Nematostella vectensis to explore regulatory programs underlying cnidocyte diversity. We identified cell type specific regulatory elements in promoter and enhancer regions and linked them to distinct gene expression programs. This analysis revealed fundamental differences between nematocytes and spirocytes and uncovered a previously unrecognized nematocyte population that expresses the nep3 toxin but lacks most other toxins. These findings highlight the complexity of cnidocyte regulation and suggest greater cellular diversity within this defining cnidarian cell type than previously appreciated.