scholarly journals Knockout of a single Sox gene resurrects an ancestral cell type in the sea anemone Nematostella vectensis

2021 ◽  
Author(s):  
Leslie S Babonis ◽  
Camille Enjolras ◽  
Abigail J Reft ◽  
Brent M Foster ◽  
Fredrik Hugosson ◽  
...  
Keyword(s):  
Cell Fate ◽  
Prey Capture ◽  
Mechanistic Explanation ◽  
Cell Types ◽  
Sea Anemone ◽  
Nematostella Vectensis ◽  
Sea Anemones ◽  
Form And Function ◽  
Sox Gene ◽  
And Function

Cnidocytes are the explosive stinging cells found only in cnidarians (corals, jellyfish, etc). Specialized for prey capture and defense, cnidocytes are morphologically complex and vary widely in form and function across taxa; how such diversity evolved is unknown. Using CRISPR/Cas9-mediated genome editing in the burrowing sea anemone Nematostella vectensis, we show that a single transcription factor (NvSox2) acts as a binary switch between two alternative cnidocyte fates. Knockout of NvSox2 caused a complete transformation of nematocytes (piercing cells) into spirocytes (ensnaring cells). The type of spirocyte induced by NvSox2 knockout (robust spirocyte) is not normally found in N. vectensis but is common in sea anemones from other habitats. Homeotic control of cell fate provides a mechanistic explanation for the discontinuous distribution of cnidocyte types across cnidarians and demonstrates how simple counts of cell types can underestimate biodiversity.

scholarly journals A novel regulatory gene promotes novel cell fate by suppressing ancestral fate in the sea anemone Nematostella vectensis

2021 ◽  
Author(s):  
Leslie S Babonis ◽  
Camille Enjolras ◽  
Joseph F Ryan ◽  
Mark Q Martindale
Keyword(s):  
Cell Fate ◽  
Functional Divergence ◽  
Regulatory Gene ◽  
Cell Lineage ◽  
Cell Types ◽  
Sea Anemone ◽  
Nematostella Vectensis ◽  
Cell Type ◽  
Neural Fate ◽  
Developmental Program

AbstractCnidocytes (“stinging cells”) are an unequivocally novel cell type used by cnidarians (corals, jellyfish, and their kin) to immobilize prey. Although they are known to share a common evolutionary origin with neurons, the developmental program that promoted the emergence of cnidocyte fate is not known. Using functional genomics in the sea anemone, Nematostella vectensis, we show that cnidocytes evolved by suppression of neural fate in a subset of neurons expressing RFamide. We further show that a single regulatory gene, a C2H2-type zinc finger transcription factor (ZNF845), coordinates both the gain of novel (cnidocyte-specific) traits and the inhibition of ancestral (neural) traits during cnidocyte development and that this gene arose by domain shuffling in the stem cnidarian. Thus, we uncover a mechanism by which a truly novel regulatory gene (ZNF845) promoted the origin of a truly novel cell type (cnidocyte) through duplication of an ancestral cell lineage (neuron) and inhibition of its ancestral identity (RFamide).SignificanceIn this study, we demonstrate how new cell types can arise in animals through duplication of an ancestral (old) cell type followed by functional divergence of the new daughter cell. Specifically, we show that stinging cells in cnidarians (jellyfish and corals) evolved by duplication of an ancestral neuron followed by inhibition of the RFamide neuropeptide it once secreted. This is the first evidence that stinging cells evolved from a specific subtype of neurons and suggests some neurons may be easier to co-opt for novel functions than others.

scholarly journals The architecture and operating mechanism of a cnidarian stinging organelle

2021 ◽  
Author(s):  
Matthew Gibson ◽  
Ahmet Karabulut ◽  
Melainia McClain ◽  
Boris Rubinstein ◽  
Sean McKinney
Keyword(s):  
Structural Complexity ◽  
Super Resolution ◽  
Operating Mechanism ◽  
Sea Anemones ◽  
Form And Function ◽  
3D Electron Microscopy ◽  
Genetic Perturbations ◽  
Resolution Imaging ◽  
The Operating Mechanism ◽  
And Function

Abstract The stingers of jellyfish, sea anemones and other cnidarians, known as nematocysts, are remarkable cellular weapons used for both predation and defense1. Nematocysts are specialized organelles which consist of a pressurized capsule containing a coiled harpoon-like thread2. These structures are in turn built within specialized cells known as nematocytes3. When triggered4, the capsule explosively discharges, ejecting the coiled thread which punctures the target and rapidly elongates by turning inside out in a process called eversion5,6. Due to the structural complexity of the thread and the extreme speed of discharge, the precise mechanics of nematocyst firing have remained elusive7. Here, using a combination of live and super-resolution imaging, 3D electron microscopy and genetic perturbations, we define the step-by-step sequence of nematocyst operation in the model sea anemone Nematostella vectensis. This analysis reveals the complex biomechanical transformations underpinning the operating mechanism of nematocysts, one of the nature’s most exquisite biological micro-machines. Further, this study will provide insight into the form and function of related cnidarian organelles and serve as a template for the design of bioinspired microdevices.

scholarly journals Mitochondrial Fission Protein 1: Emerging Roles in Organellar Form and Function in Health and Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Ugochukwu Kelvin Ihenacho ◽  
Kelsey A. Meacham ◽  
Megan Cleland Harwig ◽  
Michael E. Widlansky ◽  
R. Blake Hill
Keyword(s):  
Human Health ◽  
Neurological Disorders ◽  
Mitochondrial Fission ◽  
Cell Types ◽  
Mitochondrial Division ◽  
Form And Function ◽  
Health And Disease ◽  
Genetic Deletion ◽  
And Function

Mitochondrial fission protein 1 (Fis1) was identified in yeast as being essential for mitochondrial division or fission and subsequently determined to mediate human mitochondrial and peroxisomal fission. Yet, its exact functions in humans, especially in regard to mitochondrial fission, remains an enigma as genetic deletion of Fis1 elongates mitochondria in some cell types, but not others. Fis1 has also been identified as an important component of apoptotic and mitophagic pathways suggesting the protein may have multiple, essential roles. This review presents current perspectives on the emerging functions of Fis1 and their implications in human health and diseases, with an emphasis on Fis1’s role in both endocrine and neurological disorders.

Form and Function in Cells of the Brain

The Neuron ◽  
2015 ◽  
pp. 23-38
Author(s):  
Irwin B. Levitan ◽  
Leonard K. Kaczmarek
Keyword(s):  
Axonal Transport ◽  
Molecular Motors ◽  
Critical Role ◽  
Neuronal Cell ◽  
Cell Types ◽  
Neuronal Cell Body ◽  
Long Distance ◽  
Form And Function ◽  
And Function ◽  
The Brain

This chapter examines unique mechanisms that the neuron has evolved to establish and maintain the form required for its specialized signaling functions. Unlike some other organs, the brain contains a variety of cell types including several classes of glial cells, which play a critical role in the formation of the myelin sheath around axons and may be involved in immune responses, synaptic transmission, and long-distance calcium signaling in the brain. Neurons share many features in common with other cells (including glia), but they are distinguished by their highly asymmetrical shapes. The neuronal cytoskeleton is essential for establishing this cell shape during development and for maintaining it in adulthood. The process of axonal transport moves vesicles and other organelles to regions remote from the neuronal cell body. Proteins such as kinesin and dynein, called molecular motors, make use of the energy released by hydrolysis of ATP to drive axonal transport.

scholarly journals Subcellular Specialization of Mitochondrial Form and Function in Skeletal Muscle Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
T. Bradley Willingham ◽  
Peter T. Ajayi ◽  
Brian Glancy
Keyword(s):  
Skeletal Muscle ◽  
Energy Homeostasis ◽  
Single Cells ◽  
Muscle Cells ◽  
Cell Types ◽  
Current Data ◽  
Skeletal Muscle Cells ◽  
Form And Function ◽  
Mitochondrial Heterogeneity ◽  
And Function

Across different cell types and within single cells, mitochondria are heterogeneous in form and function. In skeletal muscle cells, morphologically and functionally distinct subpopulations of mitochondria have been identified, but the mechanisms by which the subcellular specialization of mitochondria contributes to energy homeostasis in working muscles remains unclear. Here, we discuss the current data regarding mitochondrial heterogeneity in skeletal muscle cells and highlight potential new lines of inquiry that have emerged due to advancements in cellular imaging technologies.

scholarly journals Bi-fated tendon-to-bone attachment cells are regulated by shared enhancers and KLF transcription factors

2020 ◽  
Author(s):  
Shiri Kult ◽  
Tsviya Olender ◽  
Marco Osterwalder ◽  
Sharon Krief ◽  
Ronnie Blecher-Gonen ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Cell Fate ◽  
Single Molecule ◽  
Cell Types ◽  
Underlying Mechanism ◽  
Regulatory Elements ◽  
Transcriptional Enhancer ◽  
Molecular Identity ◽  
And Function

AbstractThe connection between different tissues is vital for the development and function of any organs and systems. In the musculoskeletal system, the attachment of elastic tendons to stiff bones poses a mechanical challenge that is solved by the formation of a transitional tissue, which allows the transfer of muscle forces to the skeleton without tearing. Here, we show that tendon-to-bone attachment cells are bi-fated, activating a mixture of chondrocyte and tenocyte transcriptomes, which is regulated by sharing regulatory elements with these cells and by Krüppel-like factors transcription factors (KLF).To uncover the molecular identity of attachment cells, we first applied high-throughput RNA sequencing to murine humeral attachment cells. The results, which were validated by in situ hybridization and single-molecule in situ hybridization, reveal that attachment cells express hundreds of chondrogenic and tenogenic genes. In search for the underlying mechanism allowing these cells to express these genes, we performed ATAC sequencing and found that attachment cells share a significant fraction of accessible intergenic chromatin areas with either tenocytes or chondrocytes. Epigenomic analysis further revealed transcriptional enhancer signatures for the majority of these regions. We then examined a subset of these regions using transgenic mouse enhancer reporter. Results verified the shared activity of some of these enhancers, supporting the possibility that the transcriptome of attachment cells is regulated by enhancers with shared activities in tenocytes or chondrocytes. Finally, integrative chromatin and motif analyses, as well as the transcriptome data, indicated that KLFs are regulators of attachment cells. Indeed, blocking the expression of Klf2 and Klf4 in the developing limb mesenchyme led to abnormal differentiation of attachment cells, establishing these factors as key regulators of the fate of these cells.In summary, our findings show how the molecular identity of bi-fated attachment cells enables the formation of the unique transitional tissue that connect tendon to bone. More broadly, we show how mixing the transcriptomes of two cell types through shared enhancers and a dedicated set of transcription factors can lead to the formation of a new cell fate that connects them.

scholarly journals Specification of diverse cell types during early neurogenesis of the mouse cerebellum

2018 ◽  
Author(s):  
John W. Wizeman ◽  
Qiuxia Guo ◽  
Elliot Wilion ◽  
James Y.H. Li
Keyword(s):  
Cell Fate ◽  
Developmental Trajectories ◽  
Ventricular Zone ◽  
Cell Types ◽  
Genome Wide ◽  
Integral Role ◽  
Cerebellar Cell ◽  
Early Neurogenesis ◽  
And Function ◽  
Developing Cerebellum

SUMMARYWe applied single-cell RNA sequencing to profile genome-wide gene expression in about 9,400 individual cerebellar cells from the mouse embryo at embryonic day 13.5. Reiterative clustering identified the major cerebellar cell types and subpopulations of different lineages. Through pseudotemporal ordering to reconstruct developmental trajectories, we identified novel transcriptional programs controlling cell fate specification of populations arising from the ventricular zone and the anterior rhombic lip, two distinct germinal zones of the embryonic cerebellum. Together, our data revealed cell-specific markers for studying the cerebellum, important specification decisions, and a number of previously unknown subpopulations that may play an integral role in the formation and function of the cerebellum. Importantly, we identified a potential mechanism of vermis formation, which is affected by multiple congenital cerebellar defects. Our findings will facilitate new discovery by providing insights into the molecular and cell type diversity in the developing cerebellum.

scholarly journals Host identity and symbiotic association affects the genetic and functional diversity of the clownfish-hosting sea anemone microbiome

2019 ◽  
Author(s):  
Benjamin M. Titus ◽  
Robert Laroche ◽  
Estefanía Rodríguez ◽  
Herman Wirshing ◽  
Christopher P. Meyer
Keyword(s):  
Functional Diversity ◽  
Sea Anemone ◽  
Symbiotic Association ◽  
Sea Anemones ◽  
Metabolic Coupling ◽  
Host Anemone ◽  
Host Identity ◽  
Functional Microbial Diversity ◽  
Eukaryotic Organisms ◽  
And Function

AbstractAll eukaryotic life engages in symbioses with a diverse community of bacteria that are essential for performing basic life functions. In many cases, eukaryotic organisms form additional symbioses with other macroscopic eukaryotes. The tightly-linked physical interactions that characterize many macroscopic symbioses creates opportunities for microbial transfer, which likely affects the diversity and function of individual microbiomes, and may ultimately lead to microbiome convergence between distantly related taxa. Here, we sequence the microbiomes of five species of clownfish-hosting sea anemones that co-occur on coral reefs in the Maldives. We test the importance of evolutionary history, clownfish symbiont association, and habitat on the genetic and predicted functional diversity of the microbiome, and explore signals of microbiome convergence in anemone taxa that have evolved symbioses with clownfishes independently. Our data indicate that host identity shapes the majority of the genetic diversity of the clownfish-hosting sea anemone microbiome, but predicted functional microbial diversity analyses demonstrate a convergence among host anemone microbiomes, which reflect increased functional diversity over individuals that do not host clownfishes. Further, we identify up-regulated microbial functions in host anemones that are likely affected by clownfish presence. Taken together our study reveals an even deeper metabolic coupling between clownfishes and their host anemones, and what could be a previously unknown mutualistic benefit to anemones that are symbiotic with clownfishes.

Fashioning the vertebrate heart: earliest embryonic decisions

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2099-2117 ◽  
Author(s):  
M.C. Fishman ◽  
K.R. Chien
Keyword(s):  
Caenorhabditis Elegans ◽  
Progenitor Cells ◽  
Cell Fate ◽  
Cellular Differentiation ◽  
Higher Order ◽  
Pattern Generation ◽  
Heart Tube ◽  
Form And Function ◽  
Heart Field ◽  
And Function

Our goal here is to set out the types of unitary decisions made by heart progenitor cells, from their appearance in the heart field until they form the simple heart tube. This provides a context to evaluate cell fate, lineage and, finally, morphogenetic decisions that configure global heart form and function. Some paradigms for cellular differentiation and for pattern generation may be borrowed from invertebrates, but neither Drosophila nor Caenorhabditis elegans suffice to unravel higher order decisions. Genetic analyses in mouse and zebrafish may provide one entrance to these pathways.

scholarly journals TATA Binding Protein (TBP) Promoter Drives Ubiquitous Expression of Marker Transgene in the Adult Sea Anemone Nematostella vectensis

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1081 ◽  
Author(s):  
Yael Admoni ◽  
Itamar Kozlovski ◽  
Magda Lewandowska ◽  
Yehu Moran
Keyword(s):  
Fluorescent Protein ◽  
Binding Protein ◽  
Fluorescent Microscopy ◽  
Cell Types ◽  
Tata Binding Protein ◽  
Nematostella Vectensis ◽  
Sea Anemones ◽  
Animal Cells ◽  
Animal Evolution

Nematostella vectensis has emerged as one as the most established models of the phylum Cnidaria (sea anemones, corals, hydroids and jellyfish) for studying animal evolution. The availability of a reference genome and the relative ease of culturing and genetically manipulating this organism make it an attractive model for addressing questions regarding the evolution of venom, development, regeneration and other interesting understudied questions. We and others have previously reported the use of tissue-specific promoters for investigating the function of a tissue or a cell type of interest in vivo. However, to our knowledge, genetic regulators at the whole organism level have not been reported yet. Here we report the identification and utilization of a ubiquitous promoter to drive a wide and robust expression of the fluorescent protein mCherry. We generated animals containing a TATA binding protein (TBP) promoter upstream of the mCherry gene. Flow cytometry and fluorescent microscopy revealed expression of mCherry in diverse cell types, accounting for more than 90% of adult animal cells. Furthermore, we detected a stable mCherry expression at different life stages and throughout generations. This tool will expand the existing experimental toolbox to facilitate genetic engineering and functional studies at the whole organism level.

Sign in / Sign up

Export Citation Format

Share Document