Direct visualization of a native Wnt in vivo reveals that a long-range Wnt gradient forms by extracellular dispersal

Wnts are evolutionarily conserved signaling proteins with essential roles in development and disease that have often been thought to spread between cells and signal at a distance. However, recent studies have challenged this model, and whether long-distance extracellular Wnt dispersal occurs and is biologically relevant is debated. Understanding fundamental aspects of Wnt dispersal has been limited by challenges with observing endogenous ligands in vivo, which has prevented directly testing hypotheses. Here, we have generated functional, fluorescently tagged alleles for a C. elegans Wnt homolog and for the first time visualized a native, long-range Wnt gradient in a living animal. Live imaging of Wnt along with source and responding cell membranes provided support for free, extracellular dispersal. By limiting Wnt transfer between cells, we confirmed that extracellular spreading shapes a long-range gradient and is critical for neuroblast migration. These results provide direct evidence that Wnts spread extracellularly to regulate aspects of long-range signaling.

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Identification of a mouse protein whose homolog in Saccharomyces cerevisiae is a component of the CCR4 transcriptional regulatory complex.

Molecular and Cellular Biology ◽

10.1128/mcb.15.7.3487 ◽

1995 ◽

Vol 15 (7) ◽

pp. 3487-3495 ◽

Cited By ~ 78

Author(s):

M P Draper ◽

C Salvadore ◽

C L Denis

Keyword(s):

Saccharomyces Cerevisiae ◽

Yeast Cells ◽

Significant Similarity ◽

Eukaryotic Transcription ◽

C Elegans ◽

Mouse Protein ◽

Transcriptional Regulatory ◽

Evolutionarily Conserved ◽

Regulatory Complex

The CCR4 protein from Saccharomyces cerevisiae is a component of a multisubunit complex that is required for the regulation of a number of genes in yeast cells. We report here the identification of a mouse protein (mCAF1 [mouse CCR4-associated factor 1]) which is capable of interacting with and binding to the yeast CCR4 protein. The mCAF1 protein was shown to have significant similarity to proteins from humans, Caenorhabditis elegans, Arabidopsis thaliana, and S. cerevisiae. The yeast gene (yCAF1) had been previously cloned as the POP2 gene, which is required for expression of several genes. Both yCAF1 (POP2) and the C. elegans homolog of CAF1 were shown to genetically interact with CCR4 in vivo, and yCAF1 (POP2) physically associated with CCR4. Disruption of the CAF1 (POP2) gene in yeast cells gave phenotypes and defects in transcription similar to those observed with disruptions of CCR4, including the ability to suppress spt10-enhanced ADH2 expression. In addition, yCAF1 (POP2) when fused to LexA was capable of activating transcription. mCAF1 could also activate transcription when fused to LexA and could functionally substitute for yCAF1 in allowing ADH2 expression in an spt10 mutant background. These data imply that CAF1 is a component of the CCR4 protein complex and that this complex has retained evolutionarily conserved functions important to eukaryotic transcription.

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The expression, lamin-dependent localization and RNAi depletion phenotype for emerin inC. elegans

Journal of Cell Science ◽

10.1242/jcs.115.5.923 ◽

2002 ◽

Vol 115 (5) ◽

pp. 923-929 ◽

Cited By ~ 4

Author(s):

Yosef Gruenbaum ◽

Kenneth K. Lee ◽

Jun Liu ◽

Merav Cohen ◽

Katherine L. Wilson

Keyword(s):

Nuclear Envelope ◽

Molecular Mechanisms ◽

Cell Types ◽

Growth Conditions ◽

Rnai Phenotype ◽

Lamin B ◽

C Elegans ◽

Nuclear Lamins ◽

First Time

Emerin belongs to the LEM-domain family of nuclear membrane proteins, which are conserved in metazoans from C. elegans to humans. Loss of emerin in humans causes the X-linked form of Emery-Dreifuss muscular dystrophy(EDMD), but the disease mechanism is not understood. We have begun to address the function of emerin in C. elegans, a genetically tractable nematode. The emerin gene (emr-1) is conserved in C. elegans. We detect Ce-emerin protein in the nuclear envelopes of all cell types except sperm, and find that Ce-emerin co-immunoprecipitates with Ce-lamin from embryo lysates. We show for the first time in any organism that nuclear lamins are essential for the nuclear envelope localization of emerin during early development. We further show that four other types of nuclear envelope proteins, including fellow LEM-domain protein Ce-MAN1, as well as Ce-lamin, UNC-84 and nucleoporins do not depend on Ce-emerin for their localization. This result suggests that emerin is not essential to organize or localize the only lamin (B-type) expressed in C. elegans. We also analyzed the RNAi phenotype resulting from the loss of emerin function in C. elegans under laboratory growth conditions, and found no detectable phenotype throughout development. We propose that C. elegans is an appropriate system in which to study the molecular mechanisms of emerin function in vivo.

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Topoisomerases I and II facilitate condensin DC translocation to organize and repress X chromosomes in C. elegans

10.1101/2021.11.30.470639 ◽

2021 ◽

Author(s):

Ana Karina Morao ◽

Jun Kim ◽

Daniel Obaji ◽

Siyu Sun ◽

Sevinc Ercan

Keyword(s):

Long Range ◽

X Chromosome ◽

Molecular Motors ◽

Topoisomerase Ii ◽

Dna Looping ◽

Loop Formation ◽

X Chromosomes ◽

C Elegans ◽

And Control

Condensin complexes are evolutionarily conserved molecular motors that translocate along DNA and form loops. While condensin-mediated DNA looping is thought to direct the chain-passing activity of topoisomerase II to separate sister chromatids, it is not known if topological constraints in turn regulate loop formation in vivo. Here we applied auxin inducible degradation of topoisomerases I and II to determine how DNA topology affects the translocation of an X chromosome specific condensin that represses transcription for dosage compensation in C. elegans (condensin DC). We found that both topoisomerases colocalize with condensin DC and control its movement at different genomic scales. TOP-2 depletion hindered condensin DC translocation over long distances, resulting in accumulation around its X-specific recruitment sites and shorter Hi-C interactions. In contrast, TOP-1 depletion did not affect long-range spreading but resulted in accumulation of condensin DC within expressed gene bodies. Both TOP-1 and TOP-2 depletions resulted in X chromosome transcriptional upregulation indicating that condensin DC translocation at both scales is required for its function in gene repression. Together the distinct effects of TOP-1 and TOP-2 on condensin DC distribution revealed two distinct modes of condensin DC association with chromatin: long-range translocation that requires decatenation/unknotting of DNA and short-range translocation across genes that requires resolution of transcription-induced supercoiling.

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Microvilli-derived Extracellular Vesicles Govern Morphogenesis in Drosophila wing epithelium

10.1101/2020.11.01.363697 ◽

2020 ◽

Author(s):

Ilse Hurbain ◽

Anne-Sophie Macé ◽

Maryse Romao ◽

Lucie Sengmanivong ◽

Laurent Ruel ◽

...

Keyword(s):

Long Range ◽

Extracellular Vesicles ◽

Cell Biology ◽

Extracellular Vesicle ◽

Wing Disc ◽

Cellular Mechanisms ◽

Long Distance ◽

Drosophila Wing ◽

And Function

ABSTRACTThe regulation and coordination of developmental processes involves the secretion of morphogens and membrane carriers, including extracellular vesicles, which facilitate their transport over long distance. The long-range activity of the Hedgehog morphogen is conveyed by extracellular vesicles. However, the site and the molecular basis of their biogenesis remains unknown. By combining fluorescence and electron microscopy combined with genetics and cell biology approaches, we investigated the origin and the cellular mechanisms underlying extracellular vesicle biogenesis, and their contribution to Drosophila wing disc development, exploiting Hedgehog as a long-range morphogen. We show that microvilli of Drosophila wing disc epithelium are the site of generation of small extracellular vesicles that transport Hedgehog across the tissue. This process requires the Prominin-like protein, whose activity, together with interacting cytoskeleton components and lipids, is critical for maintaining microvilli integrity and function in secretion. Our results provide the first evidence that microvilli-derived extracellular vesicles contribute to Hedgehog long-range signaling activity highlighting their physiological significance in tissue development in vivo.

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The short- and long-range RNA-RNA Interactome of SARS-CoV-2

10.1101/2020.07.19.211110 ◽

2020 ◽

Cited By ~ 4

Author(s):

Omer Ziv ◽

Jonathan Price ◽

Lyudmila Shalamova ◽

Tsveta Kamenova ◽

Ian Goodfellow ◽

...

Keyword(s):

Long Range ◽

Rna Structure ◽

Purifying Selection ◽

Etiologic Agent ◽

Long Distance ◽

Rna Interaction ◽

Positive Strand Rna ◽

Discontinuous Transcription ◽

Transcription And Replication

SUMMARYThe Coronaviridae is a family of positive-strand RNA viruses that includes SARS-CoV-2, the etiologic agent of the COVID-19 pandemic. Bearing the largest single-stranded RNA genomes in nature, coronaviruses are critically dependent on long-distance RNA-RNA interactions to regulate the viral transcription and replication pathways. Here we experimentally mapped the in vivo RNA-RNA interactome of the full-length SARS-CoV-2 genome and subgenomic mRNAs. We uncovered a network of RNA-RNA interactions spanning tens of thousands of nucleotides. These interactions reveal that the viral genome and subgenomes adopt alternative topologies inside cells, and engage in different interactions with host RNAs. Notably, we discovered a long-range RNA-RNA interaction - the FSE-arch - that encircles the programmed ribosomal frameshifting element. The FSE-arch is conserved in the related MERS-CoV and is under purifying selection. Our findings illuminate RNA structure based mechanisms governing replication, discontinuous transcription, and translation of coronaviruses, and will aid future efforts to develop antiviral strategies.

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Carqueja (Baccharis trimera) Protects against Oxidative Stress andβ-Amyloid-Induced Toxicity inCaenorhabditis elegans

Oxidative Medicine and Cellular Longevity ◽

10.1155/2015/740162 ◽

2015 ◽

Vol 2015 ◽

pp. 1-15 ◽

Cited By ~ 9

Author(s):

Franciny Aparecida Paiva ◽

Larissa de Freitas Bonomo ◽

Patrícia Ferreira Boasquivis ◽

Igor Thadeu Borges Raposo de Paula ◽

Joyce Ferreira da Costa Guerra ◽

...

Keyword(s):

Oxidative Stress ◽

Stress Resistance ◽

Native Plant ◽

Hydroalcoholic Extract ◽

C Elegans ◽

Amyloid Toxicity ◽

First Time ◽

Baccharis Trimera

Carqueja (Baccharis trimera) is a native plant found throughout South America. Several studies have shown that Carqueja has antioxidant activityin vitro, as well as anti-inflammatory, antidiabetic, analgesic, antihepatotoxic, and antimutagenic properties. However, studies regarding its antioxidant potentialin vivoare limited. In this study, we usedCaenorhabditis elegansas a model to examine the antioxidant effects of a Carqueja hydroalcoholic extract (CHE) on stress resistance and lifespan and to investigate whether CHE has a protective effect in aC. elegansmodel for Alzheimer's disease. Here, we show for the first time, usingin vivoassays, that CHE treatment improved oxidative stress resistance by increasing survival rate and by reducing ROS levels under oxidative stress conditions independently of the stress-related signaling pathways (p38, JNK, and ERK) and transcription factors (SKN-1/Nrf and DAF-16/Foxo) tested here. CHE treatment also increased the defenses againstβ-amyloid toxicity inC. elegans, in part by increasing proteasome activity and the expression of two heat shock protein genes. Our findings suggest a potential neuroprotective use for Carqueja, supporting the idea that dietary antioxidants are a promising approach to boost the defensive systems against stress and neurodegeneration.

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Nitric oxide rapidly scavenges tyrosine and tryptophan radicals

Biochemical Journal ◽

10.1042/bj3100745 ◽

1995 ◽

Vol 310 (3) ◽

pp. 745-749 ◽

Cited By ~ 101

Author(s):

J P Eiserich ◽

J Butler ◽

A van der Vliet ◽

C E Cross ◽

B Halliwell

Keyword(s):

Nitric Oxide ◽

Biologically Relevant ◽

Tyrosine Residues ◽

Transfer Processes ◽

Diffusion Controlled ◽

Electron Transfer Processes ◽

Protein Radicals ◽

First Time

By utilizing a pulse-radiolytic technique, we demonstrate for the first time that the rate constant for the reaction of nitric oxide (.NO) with biologically relevant tyrosine and tryptophan radicals (Tyr. and Trp. respectively) in amino acids, peptides and proteins is of the order of (1-2) x 10(9) M-1.s-1. We also show that .NO effectively interferes with electron-transfer processes between tryptophan and tyrosine residues in proteins subjected to pulse radiolysis. The near diffusion-controlled rates of these reactions, coupled with the increasingly recognized role of protein radicals in enzyme catalysis and oxidative damage, suggest that Tyr. and Trp. are likely and important targets for .NO generated in vivo.

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Evolutionarily conserved roles of Caenorhabditis elegans perilipin in lipolysis

10.7287/peerj.preprints.27467v1 ◽

2019 ◽

Author(s):

Filip Kaššák ◽

Ahmed A Chughtai ◽

Marta Kostrouchová

Keyword(s):

Neutral Lipids ◽

Physiological Role ◽

Hormone Sensitive Lipase ◽

Functional Connection ◽

Regulatory Pathways ◽

C Elegans ◽

Evolutionarily Conserved ◽

Eukaryotic Organisms

Neutral lipids and namely triacyl-glycerols (TAGs) are the prevalent excess energy storage molecules in all eukaryotic organisms. They are universally organized in active cytoplasmic organelles called lipid droplets (LDs) and their breakdown is performed and regulated in an evolutionarily conserved manner. In mammals, two distinct but inter-connected pathways are believed to mediate this catabolism: conventional cytoplasmic lipolysis with effector neutral lipases; and lipophagy, a specific kind of autophagy exploiting lysosomal acidic lipases. Central molecules in this regulation are LD-resident proteins, perilipins (PLINs). Our recent discovery of a sole PLIN orthologue in C. elegans offers a unique opportunity to study these regulatory pathways, provided that the interactive mechanisms are orthologous. To determine this, we employed classical genetics with genome editing tools and in vivo microscopy to provide three lines of evidence demonstrating the conserved role of the C. elegans perilipin. Firstly, we proved the common presence of a standard lipolytic apparatus on LDs. Next, we ascertained a functional connection between nematode PLIN-1 and the effector enzyme, hormone-sensitive lipase (HOSL-1). Finally, we identified lipophagy as a secondary lipolytic pathway, which is consistent with the mammalian model. Our data provide not only a proof of concept but also suggests interesting implications by questioning the physiological role of lipophagy in lipolysis.

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Evolutionarily conserved anatomical and physiological properties of olfactory pathway till fourth order neurons in a species of grasshopper(Hieroglyphus banian)

10.1101/436626 ◽

2018 ◽

Cited By ~ 2

Author(s):

Shilpi Singh ◽

Joby Joseph

Keyword(s):

Fourth Order ◽

Antennal Lobe ◽

Olfactory Pathway ◽

New Class ◽

Physiological Properties ◽

Evolutionarily Conserved ◽

Olfactory Stimuli ◽

Olfactory Systems ◽

First Time

AbstractOlfactory systems of different species show variations in structure and physiology despite some conserved characteristics. We characterized the olfactory circuit of the grasshopperHieroglyphus banianof family Acrididae (subfamily: Hemiacridinae) and compared it to a well-studied species of locust,Schistocerca americana(subfamily: Cyrtacanthacridinae), also belonging to family Acrididae. We used in vivo electrophysiological, immunohistochemical and anatomical (bulk tract tracing) methods to elucidate the olfactory pathway from the second order neurons in antennal lobe to the fourth order neurons in β-lobe ofH. banian.We observe highly conserved anatomical and physiological characteristics till the fourth order neurons in the olfactory circuit ofH. banianandS. americana, though they are evolutionarily divergent (~57 million years ago). However, we found one major difference between the two species-there are four antennal lobe tracts inH. banianwhile only one is reported inS. americana. Besides, we are reporting for the first time, a new class of bilateral neurons which respond weakly to olfactory stimuli even though they innervate densely downstream of Kenyon cells.

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In vivo dynamics of active edema and lethal factors during anthrax

Scientific Reports ◽

10.1038/srep23346 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 15

Author(s):

Clémence Rougeaux ◽

François Becher ◽

Eric Ezan ◽

Jean-Nicolas Tournier ◽

Pierre L. Goossens

Keyword(s):

Quantitative Methods ◽

Protective Antigen ◽

Lethal Factor ◽

Infection Process ◽

Long Distance ◽

Infectious Process ◽

Edema Factor ◽

Lethal Factors ◽

First Time

Abstract Lethal and edema toxins are critical virulence factors of Bacillus anthracis. However, little is known about their in vivo dynamics of production during anthrax. In this study, we unraveled for the first time the in vivo kinetics of production of the toxin components EF (edema factor) and LF (lethal factor) during cutaneous infection with a wild-type toxinogenic encapsulated strain in immuno-competent mice. We stratified the asynchronous infection process into defined stages through bioluminescence imaging (BLI), while exploiting sensitive quantitative methods by measuring the enzymatic activity of LF and EF. LF was produced in high amounts, while EF amounts steadily increased during the infectious process. This led to high LF/EF ratios throughout the infection, with variations between 50 to a few thousands. In the bloodstream, the early detection of active LF and EF despite the absence of bacteria suggests that they may exert long distance effects. Infection with a strain deficient in the protective antigen toxin component enabled to address its role in the diffusion of LF and EF within the host. Our data provide a picture of the in vivo complexity of the infectious process.

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