scholarly journals Contemporary Transposon Tools: A Review and Guide through Mechanisms and Applications of Sleeping Beauty, piggyBac and Tol2 for Genome Engineering

2021 ◽  
Vol 22 (10) ◽  
pp. 5084
Author(s):  
Nicolás Sandoval-Villegas ◽  
Wasifa Nurieva ◽  
Maximilian Amberger ◽  
Zoltán Ivics
Keyword(s):  
Dna Sequences ◽  
Molecular Mechanisms ◽  
Gene Annotation ◽  
Sleeping Beauty ◽  
Host Cells ◽  
Marker Genes ◽  
Target Cells ◽  
Shrna Expression ◽  
Efficient Manner ◽  
Highly Efficient

Transposons are mobile genetic elements evolved to execute highly efficient integration of their genes into the genomes of their host cells. These natural DNA transfer vehicles have been harnessed as experimental tools for stably introducing a wide variety of foreign DNA sequences, including selectable marker genes, reporters, shRNA expression cassettes, mutagenic gene trap cassettes, and therapeutic gene constructs into the genomes of target cells in a regulated and highly efficient manner. Given that transposon components are typically supplied as naked nucleic acids (DNA and RNA) or recombinant protein, their use is simple, safe, and economically competitive. Thus, transposons enable several avenues for genome manipulations in vertebrates, including transgenesis for the generation of transgenic cells in tissue culture comprising the generation of pluripotent stem cells, the production of germline-transgenic animals for basic and applied research, forward genetic screens for functional gene annotation in model species and therapy of genetic disorders in humans. This review describes the molecular mechanisms involved in transposition reactions of the three most widely used transposon systems currently available (Sleeping Beauty, piggyBac, and Tol2), and discusses the various parameters and considerations pertinent to their experimental use, highlighting the state-of-the-art in transposon technology in diverse genetic applications.

scholarly journals A NanoLuc luciferase-based assay enabling the real-time analysis of protein secretion and injection by bacterial type III secretion systems

2019 ◽  
Author(s):  
Sibel Westerhausen ◽  
Melanie Nowak ◽  
Claudia Torres-Vargas ◽  
Ursula Bilitewski ◽  
Erwin Bohn ◽  
...  
Keyword(s):  
Protein Secretion ◽  
High Throughput ◽  
Type Iii Secretion ◽  
Molecular Mechanisms ◽  
Host Cells ◽  
Target Cells ◽  
Secretion Systems ◽  
Type Iii ◽  
Nanoluc Luciferase ◽  
Type Iii Secretion Systems

AbstractThe elucidation of the molecular mechanisms of secretion through bacterial protein secretion systems is impeded by a lack of assays to quantitatively assess secretion kinetics. Also the analysis of the biological role of these secretion systems as well as the identification of inhibitors targeting these systems would greatly benefit from the availability of a simple, quick and quantitative assay to monitor principle secretion and injection into host cells. Here we present a versatile solution to this need, utilizing the small and very bright NanoLuc luciferase to assess secretion and injection through the type III secretion system encoded by Salmonella pathogenicity island 1. The NanoLuc-based secretion assay features a very high signal-to-noise ratio and sensitivity down to the nanoliter scale. The assay enables monitoring of secretion kinetics and is adaptable to a high throughput screening format in 384-well microplates. We further developed NanoLuc and split-NanoLuc-based assays that enable the monitoring of type III secretion-dependent injection of effector proteins into host cells.ImportanceThe ability to secrete proteins to the bacterial cell surface, to the extracellular environment, or even into target cells is one of the foundations of interbacterial as well as pathogen-host interaction. While great progress has been made in elucidating assembly and structure of secretion systems, our understanding of their secretion mechanism often lags behind, not last because of the challenge to quantitatively assess secretion function. Here, we developed a luciferase-based assay to enable the simple, quick, quantitative, and high throughput-compatible assessment of secretion and injection through virulence-associated type III secretion systems. The assay allows detection of minute amounts of secreted substrate proteins either in the supernatant of the bacterial culture or within eukaryotic host cells. It thus provides an enabling technology to elucidate the mechanisms of secretion and injection of type III secretion systems and is likely adaptable to assay secretion through other bacterial secretion systems.

scholarly journals Galectin-1-Specific Inhibitors as a New Class of Compounds To Treat HIV-1 Infection

2011 ◽  
Vol 56 (1) ◽  
pp. 154-162 ◽  
Author(s):  
Christian St-Pierre ◽  
Michel Ouellet ◽  
Denis Giguère ◽  
Reiko Ohtake ◽  
René Roy ◽  
...  
Keyword(s):  
High Frequency ◽  
New Drugs ◽  
Host Cells ◽  
Target Cells ◽  
Efficient Manner ◽  
New Class ◽  
Antiretroviral Therapies ◽  
Leading Compounds ◽  
Hiv 1 ◽  
Replicative Cycle

ABSTRACTDespite significant improvements, antiretroviral therapies against HIV-1 are plagued by a high frequency of therapeutic failures that have been associated with acquisition of drug resistance. We recently reported that HIV-1 exploits a host glycan binding protein, galectin-1, to increase its attachment to host cells, thereby increasing its overall infectivity in susceptible cells. This finding suggests that host molecules such as galectin-1 could reduce the expected efficiency of HIV-1 drugs targeting early steps of the replicative cycle, such as attachment and entry processes. Thus, new classes of drugs that would interfere with galectin-1/HIV-1 interactions could benefit the current antiretroviral therapy. To further explore this possibility, experiments were conducted to discover leading compounds showing specific inhibition of galectin-1 activity in a cellular model of HIV-1 infection. Three lactoside compounds were found to modestly inhibit the interaction of galectin-1 with primary human CD4+T cells. Interestingly, these same inhibitors reduced the galectin-1-mediated increase in HIV-1 attachment to target cells in a much more efficient manner. More important, the tested lactoside derivatives also significantly decreased the galectin-1-dependent enhancement of HIV-1 infection. These observations deserve further attention when considering that the development of new drugs to prevent and treat HIV-1 infection remains a priority.

scholarly journals Purification and Characterization of a UDP-Glucosyltransferase Produced by Legionella pneumophila

2003 ◽  
Vol 71 (1) ◽  
pp. 181-186 ◽  
Author(s):  
Iouri Belyi ◽  
Michel R. Popoff ◽  
Nicholas P. Cianciotto
Keyword(s):  
Legionella Pneumophila ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Immunoblot Analysis ◽  
Host Cells ◽  
Target Cells ◽  
Transferase Activity ◽  
Genome Database ◽  
Intact Gene ◽  
Internal Peptide

ABSTRACT Legionella pneumophila is the agent of Legionnaires' disease. It invades and replicates within eukaryotic cells, including aquatic protozoans, mammalian macrophages, and epithelial cells. The molecular mechanisms of the Legionella interaction with target cells are not fully defined. In an attempt to discover novel virulence factors of L. pneumophila, we searched for bacterial enzymes with transferase activity. Upon screening ultrasonic extracts of virulent legionellae, we identified a uridine diphospho (UDP)-glucosyltransferase activity, which was capable of modifying a 45-kDa substrate in host cells. An approximately 60-kDa UDP-glucosyltransferase was purified from L. pneumophila and subjected to microsequencing. An N-terminal amino acid sequence, as well as the sequence of an internal peptide, allowed us to identify the gene for the enzyme within the unfinished L. pneumophila genome database. The intact gene was cloned and expressed in Escherichia coli, and the recombinant protein was purified and confirmed to possess an enzymatic activity similar to that of the native UDP-glucosyltransferase. We designated this gene ugt (UDP-glucosyltransferase). The Legionella enzyme did not exhibit significant homology with any known protein, suggesting that it is novel in structure and, perhaps, in function. Based on PCR data, an enzyme assay, and an immunoblot analysis, the glucosyltransferase appeared to be conserved in L. pneumophila strains but was absent from the other Legionella species. This study represents the first identification of a UDP-glucosyltransferase in an intracellular parasite, and therefore modification of a eukaryotic target(s) by this enzyme may influence host cell function and promote L. pneumophila proliferation.

scholarly journals A high-affinity calmodulin-binding site in the CyaA toxin translocation domain is essential for invasion into eukaryotic cells

2020 ◽  
Author(s):  
Alexis Voegele ◽  
Mirko Sadi ◽  
Darragh P O’Brien ◽  
Pauline Gehan ◽  
Dorothée Raoux-Barbot ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Chain Transfer ◽  
Catalytic Domain ◽  
Mutational Analysis ◽  
Protein Translocation ◽  
Host Cells ◽  
Target Cells ◽  
Calmodulin Binding ◽  
Translocation Domain ◽  
Key Residues

AbstractThe molecular mechanisms and forces involved in the translocation of bacterial toxins into host cells have thus far remained elusive. The adenylate cyclase (CyaA) toxin from Bordetella pertussis displays a unique intoxication pathway in which its catalytic domain is directly translocated across target cell membranes. We have previously identified a translocation region in CyaA that contains a segment, P454 (residues 454–484), exhibiting membrane-active properties related to antimicrobial peptides. Herein, we show that this peptide is able to translocate across membranes and interact with calmodulin. Structural and biophysical analyses have revealed the key residues of P454 involved in membrane destabilization and calmodulin binding. Mutational analysis demonstrated that these residues play a crucial role in CyaA translocation into target cells. We have also shown that calmidazolium, a calmodulin inhibitor, efficiently blocks CyaA internalization. We propose that after CyaA binding to target cells, the P454 segment destabilizes the plasma membrane, translocates across the lipid bilayer and binds calmodulin. Trapping of the CyaA polypeptide chain by the CaM:P454 interaction in the cytosol may assist the entry of the N-terminal catalytic domain by converting the stochastic process of protein translocation into an efficient vectorial chain transfer into host cells.

scholarly journals Mechanisms Associated with Trypanosoma cruzi Host Target Cell Adhesion, Recognition and Internalization

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 534
Author(s):  
Oscar Hernán Rodríguez-Bejarano ◽  
Catalina Avendaño ◽  
Manuel Alfonso Patarroyo
Keyword(s):  
Trypanosoma Cruzi ◽  
Host Cell ◽  
Molecular Mechanisms ◽  
Parasitophorous Vacuole ◽  
Host Cells ◽  
Mammalian Host ◽  
Target Cells ◽  
Cell Plasma ◽  
Insect Bites ◽  
Host Target

Chagas disease is caused by the kinetoplastid parasite Trypanosoma cruzi, which is mainly transmitted by hematophagous insect bites. The parasite’s lifecycle has an obligate intracellular phase (amastigotes), while metacyclic and bloodstream-trypomastigotes are its infective forms. Mammalian host cell recognition of the parasite involves the interaction of numerous parasite and host cell plasma membrane molecules and domains (known as lipid rafts), thereby ensuring internalization by activating endocytosis mechanisms triggered by various signaling cascades in both host cells and the parasite. This increases cytoplasmatic Ca2+ and cAMP levels; cytoskeleton remodeling and endosome and lysosome intracellular system association are triggered, leading to parasitophorous vacuole formation. Its membrane becomes modified by containing the parasite’s infectious form within it. Once it has become internalized, the parasite seeks parasitophorous vacuole lysis for continuing its intracellular lifecycle, fragmenting such a vacuole’s membrane. This review covers the cellular and molecular mechanisms involved in T. cruzi adhesion to, recognition of and internalization in host target cells.

scholarly journals Microfilaments and Microtubules Alternately Coordinate the Multistep Endosomal Trafficking of Classical Swine Fever Virus

2021 ◽  
Vol 95 (10) ◽  
Author(s):  
Yan Cheng ◽  
Jin-xiu Lou ◽  
Chun-chun Liu ◽  
Ya-yun Liu ◽  
Xiong-nan Chen ◽  
...  
Keyword(s):  
Classical Swine Fever Virus ◽  
Actin Filaments ◽  
Molecular Mechanisms ◽  
Classical Swine Fever ◽  
Early Endosome ◽  
Fever Virus ◽  
Late Endosome ◽  
Host Cells ◽  
Target Cells ◽  
Dynamic Changes

ABSTRACT The cytoskeleton, as a ubiquitous structure in the cells, plays an important role in the processes of virus entry, replication, and survival. However, the action mechanism of the cytoskeleton in the invasion of pestivirus into host cells remains unclear. In this study, we systematically dissected the key roles of the main cytoskeleton components, namely microfilaments and microtubules, in the endocytosis of the porcine pestivirus classical swine fever virus (CSFV). We observed the dynamic changes of actin filaments in CSFV entry. Confocal microscopy showed that CSFV invasion induced the dissolution and aggregation of stress fibers, resulting in the formation of lamellipodia and filopodia. Chemical inhibitors and RNA interference were used to find that the dynamic changes of actin were caused by an EGFR-PI3K/MAPK-RhoA/Rac1/Cdc42-cofilin signaling pathway, which regulates the microfilaments to help CSFV entry. Furthermore, colocalization of the microfilaments with clathrin and Rab5 (early endosome), as well as that of microtubules with Rab7 (late endosome) and Lamp1 (lysosome) revealed that microfilaments were activated and rearranged to help CSFV trafficking to the early endosome after endocytosis. Subsequently, recruitment of microtubules by CSFV also assisted membrane fusion of the virions from the late endosome to the lysosome with the help of a molecular motor, dynein. Unexpectedly, vimentin, which is an intermediate filament, had no effect on CSFV entry. Taken together, our findings comprehensively revealed the molecular mechanisms of cytoskeletal components that regulated CSFV endocytosis and facilitated further understanding of pestivirus entry, which would be conducive to exploration of antiviral molecules to control classical swine fever. IMPORTANCE Endocytosis, an essential biological process mediating cellular internalization events, is often exploited by pathogens for their entry into target cells. Previously, we reported different mechanisms of CSFV endocytosis into the porcine epithelial cells (PK-15) and macrophages (3D4/21); however, the details of microfilaments/microtubules mediated virus migration within the host cells remained to be elucidated. In this study, we found that CSFV infection induced rearrangement of actin filaments regulated by cofilin through an EGFR-PI3K/MAPK-RhoA/Rac1/Cdc42 pathway. Furthermore, we found that CSFV particles were trafficked along actin filaments in early and late endosomes, and through microtubules in lysosomes after entry. Here, we provide for the first time a comprehensive description of the cytoskeleton that facilitates the entry and the intracellular transport of a highly pathogenic swine virus. Results from this study will greatly contribute to the understanding of virus-induced early and complex changes in host cells that are important in CSFV pathogenesis.

Transcription factor/DNA interactions visualized by electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 450-451
Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown
Keyword(s):  
Transcription Factor ◽  
Dna Sequences ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Dna Backbone ◽  
Two Parameters ◽  
High Level

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.

scholarly journals Protective Effect of Psoralea corylifolia L. Seed Extract against Palmitate-Induced Neuronal Apoptosis in PC12 Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yunkyoung Lee ◽  
Hee-Sook Jun ◽  
Yoon Sin Oh
Keyword(s):  
Pc12 Cells ◽  
Molecular Mechanisms ◽  
Neuronal Cell ◽  
Marker Genes ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Protective Effects ◽  
Psoralea Corylifolia ◽  
Antioxidant Genes ◽  
Bax Protein

The extract of Psoralea corylifolia seeds (PCE) has been widely used as a herbal medicine because of its beneficial effect on human health. In this study, we investigated the protective effects and molecular mechanisms of PCE on palmitate- (PA-) induced toxicity in PC12 cells, a neuron-like cell line. PCE significantly increased cell viability in PA-treated PC12 cells and showed antiapoptotic effects, as evidenced by decreased expression of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, and bax protein as well as increased expression of bcl-2 protein. In addition, PCE treatment reduced PA-induced reactive oxygen species production and upregulated mRNA levels of antioxidant genes such as nuclear factor (erythroid-derived 2)-like 2 and heme oxygenase 1. Moreover, PCE treatment recovered the expression of autophagy marker genes such as beclin-1 and p62, which was decreased by PA treatment. Treatment with isopsoralen, one of the major components of PCE extract, also recovered the expression of autophagy marker genes and reduced PA-induced apoptosis. In conclusion, PCE exerts protective effects against lipotoxicity via its antioxidant function, and this effect is mediated by activation of autophagy. PCE might be a potential pharmacological agent to protect against neuronal cell injury caused by oxidative stress or lipotoxicity.

scholarly journals The Phosphatidylserine Receptor TIM-1 Enhances Authentic Chikungunya Virus Cell Entry

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1828
Author(s):  
Jared Kirui ◽  
Yara Abidine ◽  
Annasara Lenman ◽  
Koushikul Islam ◽  
Yong-Dae Gwon ◽  
...  
Keyword(s):  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Point Mutations ◽  
Cell Entry ◽  
Target Cells ◽  
Human Hepatoma Cells ◽  
Chikv Infection ◽  
Phosphatidylserine Receptor

Chikungunya virus (CHIKV) is a re-emerging, mosquito-transmitted, enveloped positive stranded RNA virus. Chikungunya fever is characterized by acute and chronic debilitating arthritis. Although multiple host factors have been shown to enhance CHIKV infection, the molecular mechanisms of cell entry and entry factors remain poorly understood. The phosphatidylserine-dependent receptors, T-cell immunoglobulin and mucin domain 1 (TIM-1) and Axl receptor tyrosine kinase (Axl), are transmembrane proteins that can serve as entry factors for enveloped viruses. Previous studies used pseudoviruses to delineate the role of TIM-1 and Axl in CHIKV entry. Conversely, here, we use the authentic CHIKV and cells ectopically expressing TIM-1 or Axl and demonstrate a role for TIM-1 in CHIKV infection. To further characterize TIM-1-dependent CHIKV infection, we generated cells expressing domain mutants of TIM-1. We show that point mutations in the phosphatidylserine binding site of TIM-1 lead to reduced binding, entry, and infection of CHIKV. Ectopic expression of TIM-1 renders immortalized keratinocytes permissive to CHIKV, whereas silencing of endogenously expressed TIM-1 in human hepatoma cells reduces CHIKV infection. Altogether, our findings indicate that, unlike Axl, TIM-1 readily promotes the productive entry of authentic CHIKV into target cells.

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