21 results on '"Radko S"'
Search Results
2. Recombinase Polymerase and Loop-Mediated Isothermal Amplification in the DNA Diagnostics of Infectious Diseases
- Author
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Kurbatov, L. K., Ptitsyn, K. G., Khmeleva, S. A., Radko, S. P., Lisitsa, A. V., and Suprun, E. V.
- Published
- 2024
- Full Text
- View/download PDF
3. Transcriptome and proteome of Chr 18: SE02–6
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Zgoda, V., Kopylov, A., Moisa, A., Lisitsa, A., Ponomarenko, E., Radko, S., Ilina, E., Govorun, V., and Archakov, A.
- Published
- 2013
4. Water vapor thermal plasma generation
- Author
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Anshakov, A S, primary, Radko, S I, additional, and Urbakh, A E, additional
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- 2020
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5. Automation of plasma technology aimed at the disposal of organic waste
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Anshakov, A S, primary, Domarov, P V, additional, Faleev, V A, additional, and Radko, S I, additional
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- 2019
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6. [Photoaptamer heterodimeric constructs as a new approach to enhance the efficiency of formation of photocrosslinking with a target protein]
- Author
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Rakhmetova, S. Yu, Radko, S. P., Gnedenko, O. V., Bodoev, N. V., Alexis Ivanov, and Archakov, A. I.
- Subjects
Ultraviolet Rays ,Lasers ,Thrombin ,Humans ,General Medicine ,Biosensing Techniques ,Aptamers, Nucleotide ,Dimerization ,General Biochemistry, Genetics and Molecular Biology - Abstract
Using two DNA aptamers selectively recognizing anion-binding exosites 1 and 2 of thrombin as a model, it has been demonstrated that their conjugation by a poly-(dT)-linker (ranging from 5 to 65 nt in length) to produce aptamer heterodimeric constructs results into affinity enhancement. The apparent dissociation constant (Kdapp) measured at the optical biosensor Biacore-3000 for complexes of thrombin with the heterodimeric constructs reached minimum values (Kdapp = 0,2-0,4 nМ) which were approximately 30-fold less than for the complexes with the primary aptamers. A photoaptamer heterodimeric construct was designed connecting photoaptamer and aptamer sequences with the poly-(dT)-linker of 35 nt long. The photoaptamer used could form photo-induced cross-links with the exosite 2 of thrombin and the aptamer used could bind to the exosite 1. The measured value of Kdapp for the photoaptamer construct was approximately 40-fold less than that for the primary photoaptamer (5,3 and 190 nM, respectively). Upon exposure to the UV radiation at 308 nm of the equimolar mixtures of thrombin with the photoaptamer construct, the equal yield of the crosslinked complexes was observed at concentrations which were lower by two orders of magnitude than in the case of the primary photoaptamer. It was found that concurrently with crosslinking to thrombin a photo-induced inactivation of the photoaptamer occurs presumably due to formation of the intermolecular crosslinking.
- Published
- 2011
7. Content of Labor Potential and Formation of the Employee Competitive Advantages in the Cultural Context
- Author
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Radko Sergei G.
- Subjects
Social Sciences - Abstract
New personnel management systems are being built in the changing socio-economic conditions. Scientific and methodological approaches that make it possible to perform in-depth research on the labor opportunities of employees are developed. The article deals with the cultural aspects of the formation of competitive advantages of the employee in the conditions of the intersection of cultures. Representation of labor potential as a socio-economic category that reflects the ability of personnel realize the goals of the enterprise is given. The provision according to which competitive advantages are a means of improving the quality of relations in the labor sphere on the basis of labor potential, considering the cultural aspects of the competitive advantages of employees is substantiated. In what way it is possible to identify the content of the components of the labor potential of workers using the tools of the competence-based approach it is shown.
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- 2021
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8. Strong Inhibitory Effect, Low Cytotoxicity and High Plasma Stability of Steroidal Inhibitors of N-Methyl-D-Aspartate Receptors With C-3 Amide Structural Motif
- Author
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Santosh Kumar Adla, Barbora Slavikova, Hana Chodounska, Vojtech Vyklicky, Marek Ladislav, Pavla Hubalkova, Barbora Krausova, Tereza Smejkalova, Michaela Nekardova, Marketa Smidkova, Lenka Monincova, Radko Soucek, Ladislav Vyklicky, and Eva Kudova
- Subjects
neurosteroid ,amide ,NMDA receptor ,plasma stability ,structure-activity relationship ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Herein, we report the synthesis, structure-activity relationship study, and biological evaluation of neurosteroid inhibitors of N-methyl-D-aspartate receptors (NMDARs) receptors that employ an amide structural motif, relative to pregnanolone glutamate (PAG) – a compound with neuroprotective properties. All compounds were found to be more potent NMDAR inhibitors (IC50 values varying from 1.4 to 21.7 μM) than PAG (IC50 = 51.7 μM). Selected compound 6 was evaluated for its NMDAR subtype selectivity and its ability to inhibit AMPAR/GABAR responses. Compound 6 inhibits the NMDARs (8.3 receptors (8.3 ± 2.1 μM) more strongly than it does at the GABAR and AMPARs (17.0 receptors (17.0 ± 0.2 μM and 276.4 ± 178.7 μM, respectively). In addition, compound 6 (10 μM) decreases the frequency of action potentials recorded in cultured hippocampal neurons. Next, compounds 3, 5–7, 9, and 10 were not associated with mitotoxicity, hepatotoxicity nor ROS induction. Lastly, we were able to show that all compounds have improved rat and human plasma stability over PAG.
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- 2018
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9. Atomic force microscopy fishing and mass spectrometry identification of gp120 on immobilized aptamers
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Ivanov YD, Bukharina NS, Pleshakova TO, Frantsuzov PA, Andreeva EY, Kaysheva AL, Zgoda VG, Izotov AA, Pavlova TI, Ziborov VS, Radko SP, Moshkovskii SA, and Archakov AI
- Subjects
Medicine (General) ,R5-920 - Abstract
Yuri D Ivanov,1 Natalia S Bukharina,1 Tatyana O Pleshakova,1 Pavel A Frantsuzov,1 Elena Yu Andreeva,1 Anna L Kaysheva,1,2 Victor G Zgoda,1 Alexander A Izotov,1 Tatyana I Pavlova,1 Vadim S Ziborov,1 Sergey P Radko,1 Sergei A Moshkovskii,1 Alexander I Archakov1 1Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia; 2PostgenTech Ltd., Moscow, Russia Abstract: Atomic force microscopy (AFM) was applied to carry out direct and label-free detection of gp120 human immunodeficiency virus type 1 envelope glycoprotein as a target protein. This approach was based on the AFM fishing of gp120 from the analyte solution using anti-gp120 aptamers immobilized on the AFM chip to count gp120/aptamer complexes that were formed on the chip surface. The comparison of image contrasts of fished gp120 against the background of immobilized aptamers and anti-gp120 antibodies on the AFM images was conducted. It was shown that an image contrast of the protein/aptamer complexes was two-fold higher than the contrast of the protein/antibody complexes. Mass spectrometry identification provided an additional confirmation of the target protein presence on the AFM chips after biospecific fishing to avoid any artifacts. Keywords: gp120 HIV-1 envelope glycoprotein, aptamer, atomic force microscopy, mass spectrometry
- Published
- 2014
10. Reconstitution of calcium-triggered membrane fusion using "reserve" granules.
- Author
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Chestkov, V V, Radko, S P, Cho, M S, Chrambach, A, and Vogel, S S
- Abstract
Calcium-gated secretion of proteins involves the transfer of "reserve" granules, exocytotic vesicles that are cytoplasmic and, hence, plasma membrane-naive, from the cell interior to the surface membrane where they dock prior to fusion. Docking and subsequent priming steps are thought to require cytoplasmic factors. These steps are believed to induce fusion competence. We have tested this hypothesis by isolating reserve granules from sea urchin eggs and determining under which conditions these granules will fuse. We find that isolated reserve granules, lacking soluble cofactors, support calcium-dependent membrane fusion in vitro. Preincubation with adenosine 5'-3-O-(thio)triphosphate and guanosine 5'-3-O-(thio)triphosphate did not prevent fusion. Thus, isolated reserve granules have all the necessary components required for calcium-gated fusion prior to docking.
- Published
- 1998
11. Comparison of Alternative Splicing Landscapes Revealed by Long-Read Sequencing in Hepatocyte-Derived HepG2 and Huh7 Cultured Cells and Human Liver Tissue.
- Author
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Kozlova A, Sarygina E, Deinichenko K, Radko S, Ptitsyn K, Khmeleva S, Kurbatov L, Spirin P, Prassolov V, Ilgisonis E, Lisitsa A, and Ponomarenko E
- Abstract
The long-read RNA sequencing developed by Oxford Nanopore Technologies provides a direct quantification of transcript isoforms, thereby making it possible to present alternative splicing (AS) profiles as arrays of single splice variants with different abundances. Additionally, AS profiles can be presented as arrays of genes characterized by the degree of alternative splicing (the DAS-the number of detected splice variants per gene). Here, we successfully utilized the DAS to reveal biological pathways influenced by the alterations in AS in human liver tissue and the hepatocyte-derived malignant cell lines HepG2 and Huh7, thus employing the mathematical algorithm of gene set enrichment analysis. Furthermore, analysis of the AS profiles as abundances of single splice variants by using the graded tissue specificity index τ provided the selection of the groups of genes expressing particular splice variants specifically in liver tissue, HepG2 cells, and Huh7 cells. The majority of these splice variants were translated into proteins products and appeal to be in focus regarding further insights into the mechanisms underlying cell malignization. The used metrics are intrinsically suitable for transcriptome-wide AS profiling using long-read sequencing.
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- 2023
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12. Principal Component Analysis of Alternative Splicing Profiles Revealed by Long-Read ONT Sequencing in Human Liver Tissue and Hepatocyte-Derived HepG2 and Huh7 Cell Lines.
- Author
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Sarygina E, Kozlova A, Deinichenko K, Radko S, Ptitsyn K, Khmeleva S, Kurbatov LK, Spirin P, Prassolov VS, Ilgisonis E, Lisitsa A, and Ponomarenko E
- Subjects
- Humans, Principal Component Analysis, Gene Expression Profiling methods, Transcriptome, Sequence Analysis, RNA methods, Liver, Protein Isoforms genetics, Hepatocytes, Cell Line, Alternative Splicing, High-Throughput Nucleotide Sequencing methods
- Abstract
The long-read RNA sequencing developed by Oxford Nanopore Technology provides a direct quantification of transcript isoforms. That makes the number of transcript isoforms per gene an intrinsically suitable metric for alternative splicing (AS) profiling in the application to this particular type of RNA sequencing. By using this simple metric and recruiting principal component analysis (PCA) as a tool to visualize the high-dimensional transcriptomic data, we were able to group biospecimens of normal human liver tissue and hepatocyte-derived malignant HepG2 and Huh7 cells into clear clusters in a 2D space. For the transcriptome-wide analysis, the clustering was observed regardless whether all genes were included in analysis or only those expressed in all biospecimens tested. However, in the application to a particular set of genes known as pharmacogenes, which are involved in drug metabolism, the clustering worsened dramatically in the latter case. Based on PCA data, the subsets of genes most contributing to biospecimens' grouping into clusters were selected and subjected to gene ontology analysis that allowed us to determine the top 20 biological processes among which translation and processes related to its regulation dominate. The suggested metrics can be a useful addition to the existing metrics for describing AS profiles, especially in application to transcriptome studies with long-read sequencing.
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- 2023
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13. Genome of the Single Human Chromosome 18 as a "Gold Standard" for Its Transcriptome.
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Ilgisonis E, Vavilov N, Ponomarenko E, Lisitsa A, Poverennaya E, Zgoda V, Radko S, and Archakov A
- Abstract
The cutoff level applied in sequencing analysis varies according to the sequencing technology, sample type, and study purpose, which can largely affect the coverage and reliability of the data obtained. In this study, we aimed to determine the optimal combination of parameters for reliable RNA transcriptome data analysis. Toward this end, we compared the results obtained from different transcriptome analysis platforms (quantitative polymerase chain reaction, Illumina RNASeq, and Oxford Nanopore Technologies MinION) for the transcriptome encoded by human chromosome 18 (Chr 18) using the same sample types (HepG2 cells and liver tissue). A total of 275 protein-coding genes encoded by Chr 18 was taken as the gene set for evaluation. The combination of Illumina RNASeq and MinION nanopore technologies enabled the detection of at least one transcript for each protein-coding gene encoded by Chr 18. This combination also reduced the probability of false-positive detection of low-copy transcripts due to the simultaneous confirmation of the presence of a transcript by the two fundamentally different technologies: short reads essential for reliable detection (Illumina RNASeq) and long-read sequencing data (MinION). The combination of these technologies achieved complete coverage of all 275 protein-coding genes on Chr 18, identifying transcripts with non-zero expression levels. This approach can improve distinguishing the biological and technical reasons for the absence of mRNA detection for a given gene in transcriptomics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Ilgisonis, Vavilov, Ponomarenko, Lisitsa, Poverennaya, Zgoda, Radko and Archakov.)
- Published
- 2021
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14. Human Chr18 transcriptome dataset combined from the Illumina HiSeq, ONT MinION, and qPCR data.
- Author
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Krasnov G, Shkrigunov T, Radko S, Ptitsyn K, Shapovalova V, Timoshenko O, Khmeleva S, Kurbatov L, Kiseleva Y, Ilgisonis E, Kiseleva O, Vakhrushev I, Tsvetkova A, Buromski I, Markin S, Archakov A, Lisitsa A, and Ponomarenko E
- Abstract
The chromosome-centric dataset was created by applying several technologies of transcriptome profiling. The described dataset is available at NCBI repository (BioProject ID PRJNA635536). The dataset referred to the same type of tissue, cell lines, transcriptome sequencing technologies, and was accomplished in a period of 8 years (the first data were obtained in 2013 while the last ones - in 2020). The high-throughput sequencing technologies were employed along with the quantitative PCR (qPCR) approach, for data generation using the gene expression level assessment. qPCR was performed for a limited group of genes, encoded on human chromosome 18, for the Russian part of the Chromosome-Centric Human Proteome Project. The data of high-throughput sequencing are provided as Excel spreadsheets, where the data on FPKM and TMP values were evaluated for the whole transcriptome with both Illumina HiSeq and Oxford Nanopore Technologies MinION sequencing., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article., (© 2021 The Author(s). Published by Elsevier Inc.)
- Published
- 2021
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15. Evaluation of Aptamers as Affinity Reagents for an Enhancement of SRM-Based Detection of Low-Abundance Proteins in Blood Plasma.
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Radko S, Ptitsyn K, Novikova S, Kiseleva Y, Moysa A, Kurbatov L, Mannanova M, Zgoda V, Ponomarenko E, Lisitsa A, and Archakov A
- Abstract
Selected reaction monitoring (SRM) is a mass spectrometric technique characterized by the exceptionally high selectivity and sensitivity of protein detection. However, even with this technique, the quantitative detection of low- and ultralow-abundance proteins in blood plasma, which is of great importance for the search and verification of novel protein disease markers, is a challenging task due to the immense dynamic range of protein abundance levels. One approach used to overcome this problem is the immunoaffinity enrichment of target proteins for SRM analysis, employing monoclonal antibodies. Aptamers appear as a promising alternative to antibodies for affinity enrichment. Here, using recombinant protein SMAD4 as a model target added at known concentrations to human blood plasma and SRM as a detection method, we investigated a relationship between the initial amount of the target protein and its amount in the fraction enriched with SMAD4 by an anti-SMAD4 DNA-aptamer immobilized on magnetic beads. It was found that the aptamer-based enrichment provided a 30-fold increase in the sensitivity of SRM detection of SMAD4. These results indicate that the aptamer-based affinity enrichment of target proteins can be successfully employed to improve quantitative detection of low-abundance proteins by SRM in undepleted human blood plasma.
- Published
- 2020
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16. Small-Molecule and CRISPR Screening Converge to Reveal Receptor Tyrosine Kinase Dependencies in Pediatric Rhabdoid Tumors.
- Author
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Oberlick EM, Rees MG, Seashore-Ludlow B, Vazquez F, Nelson GM, Dharia NV, Weir BA, Tsherniak A, Ghandi M, Krill-Burger JM, Meyers RM, Wang X, Montgomery P, Root DE, Bieber JM, Radko S, Cheah JH, Hon CS, Shamji AF, Clemons PA, Park PJ, Dyer MA, Golub TR, Stegmaier K, Hahn WC, Stewart EA, Schreiber SL, and Roberts CWM
- Subjects
- Animals, Antineoplastic Agents therapeutic use, CRISPR-Cas Systems, Cell Line, Tumor, Female, HEK293 Cells, Humans, Mice, Mice, Nude, Mutation, Protein Kinase Inhibitors therapeutic use, Protein Tyrosine Phosphatase, Non-Receptor Type 11 genetics, Rhabdoid Tumor drug therapy, Small Molecule Libraries pharmacology, Antineoplastic Agents pharmacology, Protein Kinase Inhibitors pharmacology, Protein Tyrosine Phosphatase, Non-Receptor Type 11 antagonists & inhibitors, Rhabdoid Tumor genetics
- Abstract
Cancer is often seen as a disease of mutations and chromosomal abnormalities. However, some cancers, including pediatric rhabdoid tumors (RTs), lack recurrent alterations targetable by current drugs and need alternative, informed therapeutic options. To nominate potential targets, we performed a high-throughput small-molecule screen complemented by a genome-scale CRISPR-Cas9 gene-knockout screen in a large number of RT and control cell lines. These approaches converged to reveal several receptor tyrosine kinases (RTKs) as therapeutic targets, with RTK inhibition effective in suppressing RT cell growth in vitro and against a xenograft model in vivo. RT cell lines highly express and activate (phosphorylate) different RTKs, creating dependency without mutation or amplification. Downstream of RTK signaling, we identified PTPN11, encoding the pro-growth signaling protein SHP2, as a shared dependency across all RT cell lines. This study demonstrates that large-scale perturbational screening can uncover vulnerabilities in cancers with "quiet" genomes., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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17. Adenovirus 5 E1A-Mediated Suppression of p53 via FUBP1.
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Frost JR, Mendez M, Soriano AM, Crisostomo L, Olanubi O, Radko S, and Pelka P
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- Adenoviridae Infections metabolism, Adenovirus E1A Proteins genetics, Cells, Cultured, DNA Helicases genetics, DNA-Binding Proteins genetics, Fibroblasts cytology, Fibroblasts metabolism, Fibroblasts virology, Gene Expression Regulation, Viral, Humans, Promoter Regions, Genetic, Protein Binding, RNA-Binding Proteins, Transcriptional Activation, Tumor Suppressor Protein p53 antagonists & inhibitors, Tumor Suppressor Protein p53 genetics, Adenoviridae physiology, Adenoviridae Infections virology, Adenovirus E1A Proteins metabolism, DNA Helicases metabolism, DNA-Binding Proteins metabolism, Host-Pathogen Interactions, Tumor Suppressor Protein p53 metabolism, Virus Replication
- Abstract
Far-upstream element (FUSE) binding protein 1 (FUBP1) was originally identified as a regulator of the oncogene c-Myc via binding to the FUSE within the c-Myc promoter and activating the expression of the gene. Recent studies have identified FUBP1 as a regulator of transcription, translation, and splicing via its DNA and RNA binding activities. Here we report the identification of FUBP1 as a novel binding partner of E1A. FUBP1 binds directly to E1A via the N terminus (residues 1 to 82) and conserved region 3 (residues 139 to 204) of adenovirus 5 E1A. The depletion of FUBP1 via short interfering RNAs (siRNA) reduces virus growth and drives the upregulation of the cellular stress response by activating the expression of p53-regulated genes. During infection, FUBP1 is relocalized within the nucleus, and it is recruited to viral promoters together with E1A while at the same time being lost from the FUSE upstream of the c-Myc promoter. The depletion of FUBP1 affects viral and cellular gene expression. Importantly, in FUBP1-depleted cells, p53-responsive genes are upregulated, p53 occupancy on target promoters is enhanced, and histone H3 lysine 9 is hyperacetylated. This is likely due to the loss of the FUBP1-mediated suppression of p53 DNA binding. We also observed that E1A stabilizes the FUBP1-p53 complex, preventing p53 promoter binding. Together, our results identify, for the first time, FUBP1 as a novel E1A binding protein that participates in aspects of viral replication and is involved in the E1A-mediated suppression of p53 function. IMPORTANCE Viral infection triggers innate cellular defense mechanisms that have evolved to block virus replication. To overcome this, viruses have counterevolved mechanisms that ensure that cellular defenses are either disarmed or not activated to guarantee successful replication. One of the key regulators of cellular stress is the tumor suppressor p53 that responds to a variety of cellular stress stimuli and safeguards the integrity of the genome. During infection, many viruses target the p53 pathway in order to deactivate it. Here we report that human adenovirus 5 coopts the cellular protein FUBP1 to prevent the activation of the p53 stress response pathway that would block viral replication. This finding adds to our understanding of p53 deactivation by adenovirus and highlights its importance in infection and innate immunity., (Copyright © 2018 American Society for Microbiology.)
- Published
- 2018
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18. Suppression of Type I Interferon Signaling by E1A via RuvBL1/Pontin.
- Author
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Olanubi O, Frost JR, Radko S, and Pelka P
- Subjects
- ATPases Associated with Diverse Cellular Activities, Cell Line, Humans, Immune Evasion, Immunity, Innate, Promoter Regions, Genetic, Protein Binding, Protein Interaction Mapping, Signal Transduction, Adenoviridae immunology, Adenovirus E1A Proteins metabolism, Carrier Proteins metabolism, DNA Helicases metabolism, Host-Pathogen Interactions, Immune Tolerance, Interferon Type I antagonists & inhibitors
- Abstract
Suppression of interferon signaling is of paramount importance to a virus. Interferon signaling significantly reduces or halts the ability of a virus to replicate; therefore, viruses have evolved sophisticated mechanisms that suppress activation of the interferon pathway or responsiveness of the infected cell to interferon. Adenovirus has multiple modes of inhibiting the cellular response to interferon. Here, we report that E1A, previously shown to regulate interferon signaling in multiple ways, inhibits interferon-stimulated gene expression by modulating RuvBL1 function. RuvBL1 was previously shown to affect type I interferon signaling. E1A binds to RuvBL1 and is recruited to RuvBL1-regulated promoters in an interferon-dependent manner, preventing their activation. Depletion of RuvBL1 impairs adenovirus growth but does not appear to significantly affect viral protein expression. Although RuvBL1 has been shown to play a role in cell growth, its depletion had no effect on the ability of the virus to replicate its genome or to drive cells into S phase. E1A was found to bind to RuvBL1 via the C terminus of E1A, and this interaction was important for suppression of interferon-stimulated gene transcriptional activation and recruitment of E1A to interferon-regulated promoters. Here, we report the identification of RuvBL1 as a new target for adenovirus in its quest to suppress the interferon response. IMPORTANCE For most viruses, suppression of the interferon signaling pathway is crucial to ensure a successful replicative cycle. Human adenovirus has evolved several different mechanisms that prevent activation of interferon or the ability of the cell to respond to interferon. The viral immediate-early gene E1A was previously shown to affect interferon signaling in several different ways. Here, we report a novel mechanism reliant on RuvBL1 that E1A uses to prevent activation of interferon-stimulated gene expression following infection or interferon treatment. This adds to the growing knowledge of how viruses are able to inhibit interferon and identifies a novel target used by adenovirus for modulation of the cellular interferon pathway., (Copyright © 2017 American Society for Microbiology.)
- Published
- 2017
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19. The Dual Nature of Nek9 in Adenovirus Replication.
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Jung R, Radko S, and Pelka P
- Subjects
- Cell Line, Gene Expression Regulation, Viral, Humans, NIMA-Related Kinases, Adenoviruses, Human physiology, Host-Pathogen Interactions, Protein Serine-Threonine Kinases metabolism, Virus Replication
- Abstract
Unlabelled: To successfully replicate in an infected host cell, a virus must overcome sophisticated host defense mechanisms. Viruses, therefore, have evolved a multitude of devices designed to circumvent cellular defenses that would lead to abortive infection. Previous studies have identified Nek9, a cellular kinase, as a binding partner of adenovirus E1A, but the biology behind this association remains a mystery. Here we show that Nek9 is a transcriptional repressor that functions together with E1A to silence the expression of p53-inducible GADD45A gene in the infected cell. Depletion of Nek9 in infected cells reduces virus growth but unexpectedly enhances viral gene expression from the E2 transcription unit, whereas the opposite occurs when Nek9 is overexpressed. Nek9 localizes with viral replication centers, and its depletion reduces viral genome replication, while overexpression enhances viral genome numbers in infected cells. Additionally, Nek9 was found to colocalize with the viral E4 orf3 protein, a repressor of cellular stress response. Significantly, Nek9 was also shown to associate with viral and cellular promoters and appears to function as a transcriptional repressor, representing the first instance of Nek9 playing a role in gene regulation. Overall, these results highlight the complexity of virus-host interactions and identify a new role for the cellular protein Nek9 during infection, suggesting a role for Nek9 in regulating p53 target gene expression., Importance: In the arms race that exists between a pathogen and its host, each has continually evolved mechanisms to either promote or prevent infection. In order to successfully replicate and spread, a virus must overcome every mechanism that a cell can assemble to block infection. On the other hand, to counter viral spread, cells must have multiple mechanisms to stifle viral replication. In the present study, we add to our understanding of how the human adenovirus is able to circumvent cellular roadblocks to replication. We show that the virus uses a cellular protein, Nek9, in order to block activation of p53-regulated gene GADD45A, which is an important player in stress response and p53-mediated cell cycle arrest. Importantly, our study also identifies Nek9 as a transcriptional repressor., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
- Full Text
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20. Effects of Adenovirus Type 5 E1A Isoforms on Viral Replication in Arrested Human Cells.
- Author
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Radko S, Jung R, Olanubi O, and Pelka P
- Subjects
- Cell Line, Cell Proliferation, Cell Shape, DNA Replication, Fibroblasts physiology, Fibroblasts virology, Humans, Protein Isoforms physiology, S Phase Cell Cycle Checkpoints, Adenoviridae physiology, Adenovirus E1A Proteins physiology, Virus Replication
- Abstract
Human adenovirus has evolved to infect and replicate in terminally differentiated human epithelial cells, predominantly those within the airway, the gut, or the eye. To overcome the block to viral DNA replication present in these cells, the virus expresses the Early 1A proteins (E1A). These immediate early proteins drive cells into S-phase and induce expression of all other viral early genes. During infection, several E1A isoforms are expressed with proteins of 289, 243, 217, 171, and 55 residues being present for human adenovirus type 5. Here we examine the contribution that the two largest E1A isoforms make to the viral life cycle in growth-arrested normal human fibroblasts. Viruses that express E1A289R were found to replicate better than those that do not express this isoform. Importantly, induction of several viral genes was delayed in a virus expressing E1A243R, with several viral structural proteins undetectable by western blot. We also highlight the changes in E1A isoforms detected during the course of viral infection. Furthermore, we show that viral DNA replication occurs more efficiently, leading to higher number of viral genomes in cells infected with viruses that express E1A289R. Finally, induction of S-phase specific genes differs between viruses expressing different E1A isoforms, with those having E1A289R leading to, generally, earlier activation of these genes. Overall, we provide an overview of adenovirus replication using modern molecular biology approaches and further insights into the contribution that E1A isoforms make to the life cycle of human adenovirus in arrested human fibroblasts.
- Published
- 2015
- Full Text
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21. Adenovirus E1A targets the DREF nuclear factor to regulate virus gene expression, DNA replication, and growth.
- Author
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Radko S, Koleva M, James KM, Jung R, Mymryk JS, and Pelka P
- Subjects
- Adenoviruses, Human genetics, Adenoviruses, Human growth & development, Cell Line, DNA Replication, Gene Expression Regulation, Viral, Humans, Protein Binding, Protein Interaction Mapping, Adenovirus E1A Proteins metabolism, Adenoviruses, Human physiology, Host-Pathogen Interactions, Transcription Factors metabolism, Virus Replication
- Abstract
Unlabelled: The adenovirus E1A gene is the first gene expressed upon viral infection. E1A remodels the cellular environment to maximize permissivity for viral replication. E1A is also the major transactivator of viral early gene expression and a coregulator of a large number of cellular genes. E1A carries out its functions predominantly by binding to cellular regulatory proteins and altering their activities. The unstructured nature of E1A enables it to bind to a large variety of cellular proteins and form new molecular complexes with novel functions. The C terminus of E1A is the least-characterized region of the protein, with few known binding partners. Here we report the identification of cellular factor DREF (ZBED1) as a novel and direct binding partner of E1A. Our studies identify a dual role for DREF in the viral life cycle. DREF contributes to activation of gene expression from all viral promoters early in infection. Unexpectedly, it also functions as a growth restriction factor for adenovirus as knockdown of DREF enhances virus growth and increases viral genome copy number late in the infection. We also identify DREF as a component of viral replication centers. E1A affects the subcellular distribution of DREF within PML bodies and enhances DREF SUMOylation. Our findings identify DREF as a novel E1A C terminus binding partner and provide evidence supporting a role for DREF in viral replication., Importance: This work identifies the putative transcription factor DREF as a new target of the E1A oncoproteins of human adenovirus. DREF was found to primarily localize with PML nuclear bodies in uninfected cells and to relocalize into virus replication centers during infection. DREF was also found to be SUMOylated, and this was enhanced in the presence of E1A. Knockdown of DREF reduced the levels of viral transcripts detected at 20 h, but not at 40 h, postinfection, increased overall virus yield, and enhanced viral DNA replication. DREF was also found to localize to viral promoters during infection together with E1A. These results suggest that DREF contributes to activation of viral gene expression. However, like several other PML-associated proteins, DREF also appears to function as a growth restriction factor for adenovirus infection., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
- Full Text
- View/download PDF
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