Author: Marion Declercq Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
RNA decay is a central cellular process as it regulates RNA stability and quality and thereby gene expression, which is essential to ensure proper cellular physiology and establishment of adapted responses to viral infection. Global takeover of gene expression machineries and rewiring of the cellular environment is key to the success of viral infection. Cellular proteome and viral replication are tightly connected and cellular RNA processing, stability, quality and decay accordingly influence the fate of the viral cycle. Growing evidence points towards the existence of a large interplay between eukaryotic RNA turnover machineries and viral proteins. Viruses not only evolved mechanisms to evade those RNA degradation pathways, but they also manipulate them to promote viral replication.Influenza A viruses (IAV) are major pathogens responsible for yearly epidemics and occasional pandemics. To complete their viral cycle, IAVs rely on many cellular proteins and establish a complex and highly coordinated interplay with the host proteome. Growing evidence supports the existence of a complex interplay between IAV viral proteins and RNA decay machineries. Unraveling such interplay is therefore essential to gain a better understanding of the IAV life cycle, required for the development of antiviral strategies. This led us to systematically screen interactions between viral proteins involved in IAV replication and a selected set of 75 cellular proteins carrying exoribonucleases activities or associated with RNA decay machineries. A total of 18 proteins were identified as interactors of at least one viral protein tested. Analysis of the interaction network highlighted a specific and preferential targeting of RNA degradation pathways by IAV proteins. Among validated interactors, a targeted RNAi screen identified nine factors as required for viral multiplication. We chose to focus on the 3'-5' exoribonuclease 1 (ERI1), found in our screen as an interactor of several components of the vRNPs (viral RiboNucleoProtein) (PB2, PB1 and NP). The ERI1 protein is a major player in the control of cellular gene expression as it is essential for the maturation and decay of histone mRNA, maturation of 5.8S rRNA and miRNA homeostasis in mammalian cells. Exploring the interplay between ERI1 and viral proteins during the course of IAV infection we found that i) ERI1 promotes viral transcription, and both of its activities - RNA binding and exonuclease - are required, ii) ERI1 interacts with viral proteins in an RNA dependent manner, iii) ERI1 interacts with the transcribing vRNPs, iv) viral proteins interact with a form of ERI1 that is associated to histone mRNA. Ultimately, our data point to a model where ERI1 associated to histone mRNA is co-opted by the transcribing viral polymerase, thereby promoting IAV multiplication, through a mechanism that remains to be precisely determined. Targeting of ERI1 by IAV is another example further supporting the intricate interplay between IAV and RNA decay machineries, used to rewire cellular gene expression in order to create a favorable environment for viral replication.
Author: Chutikarn Chaimayo Publisher: ISBN: Category : Languages : en Pages : 201
Book Description
Influenza A virus contains eight single-stranded, negative-sense RNA segmented genomes, which allow genetic reassortment between human and animal strains, leading to many virus pandemics. In addition to genetic reassortment, efficient regulation of host response is required for virus adaptation and transmission to different hosts. In this study, we investigated the processes of influenza genome packaging and assembly, as well as how the virus modulates host antiviral gene expression to unveil the mechanism of host adaptation. Influenza viruses replicate in the nucleus, where both genomic nucleocapsids (vRNPs) and the positive-sense complementary RNPs (cRNPs) are produced. Despite the structural similarity to vRNPs, cRNPs are not incorporated into progeny virions. To determine the mechanism by which cRNP packaging is restricted, we analyzed cRNP intracellular localization using strand-specific qRT-PCR. Our findings demonstrated that cRNPs were exported from the nucleus in a chromosome region maintenance 1 (CRM1) -independent manner. However, viral matrix (M1) protein explicitly interacted with cytosolic vRNPs, but not cRNPs, at the plasma membrane. Hence, our data indicate that a specific interaction with M1 during viral assembly determines selective incorporation of vRNPs into progeny virions. Influenza A viruses regulate host gene expression through two accessory proteins, NS1 and a novel PA-X protein expressed from ribosomal frameshifting of PA mRNA. Their shutoff activities vary between viruses from different host origins, suggesting a functional interplay between these two proteins. To analyze the effect of PA-X and NS1 on host gene expression and identify their target mRNAs, we generated four recombinant A/California/04/2009 viruses with various PA-X and NS1 shutoff activities. Our transcriptome analysis of infected human lung epithelial cells indicates that PA-X induced general gene shutoff, while NS1 specifically inhibited genes involved in interferon and cytokine signaling pathways. The virus expressing active NS1 with reduced PA-X activity most efficiently suppressed antiviral and innate immune responses in human cells, suggesting that NS1 and PA-X shutoff activities are precisely adjusted to achieve productive viral replication in human hosts. The mechanism of action and functional domains of PA-X have not been fully elucidated. Our data showed that PA-X was localized equally in the nucleus and cytoplasm, and degraded host mRNAs at both sites. By characterizing PA-X Cterminal deletion mutants, we found that the first 15 residues in the unique C-terminal domain were sufficient for host mRNA degradation and required for nuclear localization of PA-X. Our co-immunoprecipitation result showed that PA-X interacted with host factors that are either involved in pre-mRNA processing or associated with mature mRNAs. Collectively, this study sheds light on virus-host interaction and mechanisms by which influenza A viruses regulate viral assembly and host gene expression.
Author: Robert G. Webster Publisher: John Wiley & Sons ISBN: 111863683X Category : Medical Languages : en Pages : 684
Book Description
The Textbook of Influenza is a comprehensive resource covering all aspects of influenza, from the genetic and molecular biology of the virus through to clinical aspects of the disease and the latest drug developments and treatments. This new edition has been completely revised and reflects the integration of disciplines concerning the emergence, evolution, pathogenesis and control of influenza viruses in the field of human and veterinary public health. Textbook of Influenza examines the lessons learnt from the latest pandemic and provides the current state of knowledge for many yet unresolved issues related to virus origin, spread, pathogenesis and disease severity to better prepare for future pandemics. It covers the background to recent advances in influenza genomics and reverse genetics which have allowed the identification of virus virulence factors and the analysis and reconstruction of influenza viruses such as the 1918 Spanish flu strain. This new edition is divided into eight key sections, containing chapters co-written by international experts from both the clinical and scientific communities, covering: • Influenza Perspectives • Structure and Replication • Evolution and Ecology • Epidemiology and Surveillance • Immunology • Vaccines and Vaccine Development • Clinical Aspects and Antivirals • Public Health Textbook of Influenza is for all those working in the area of influenza including clinical and basic scientists, immunologists, molecular and structural virologists, public health officials and global pandemic control planners.
Author: Elise Biquand Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
An estimated 10%-20% of the world's population is affected each year by seasonal epidemic influenza, causing about 250,000 to 500,000 fatal cases. The pandemic risk reinforces the trait of influenza A virus (IAV) infection as a public health issue. The virus life cycle critically relies on its ability to manipulate the host proteome. Besides, the ubiquitin-proteasome system (UPS) is involved in many regulatory processes in mammalian cells by inducing protein degradation, mediating protein activation or shaping their sub-cellular localisation. Therefore, UPS is a prime target hijacked by viruses. Recent evidence indicates that an intricate regulatory network involving viral proteins and the cellular UPS is likely to contribute to viral replication and immune evasion of influenza A viruses. However, usurpation of the host UPS by IAV is far from being comprehensively deciphered. To gain better understanding, we assessed the interplay between the human UPS and the PB2 subunit of the influenza A virus polymerase through a global proteomic profiling approach. For that purpose, an UPS-dedicated library of 590 human cDNAs, comprising 63% of the whole human UPS, was constituted and characterised. In an initial screen, UPS factors were challenged using a high-throughput split luciferase assay for interaction with the PB2 protein from 5 influenza A strains of different pathogenicity in human. A total of 80 UPS factors emerged as potential PB2 partners, of which 42 were validated as high-confidence PB2 partners for at least one of the strains. Further comparison of interaction profiles of the 5 PB2 with the UPS by hierarchical clustering revealed an interaction dendrogram fitting with the circulation time in the human population.Functional importance of interactors was tested by siRNA-mediated knock down experiments using luciferase tagged recombinant IAV viruses. Depletion of 36 out of the 42 tested UPS factors showed an effect on the infection with all or a subset of IAV strains, underlying the strong functional output of the developed methodology. Among these factors three deubiquitinases (DUBs) were further studied to decipher their involvement in IAV viral cycle. We have shown that they are involved in early and late stage of the infection and began to draw their function in viral cycle. We demonstrated with our colleagues in Hong-Kong that OTUB1 is involved in the host cytokine response and most probably in virus assembly. OTUD6A was also shown to be implicated in late stages of the infection but we still don't know its exact role. Contrariwise, the inactive DUB PAN2, which is part of poly-deadenylation complexes, is implicated in early phase of IAV infection, but surprisingly apparently not through viral mRNA regulation. More work is on-going to precise by which mechanisms these DUBs are implicated in IAV infection.
Author: Ann Arvin Publisher: Cambridge University Press ISBN: 1139461648 Category : Medical Languages : en Pages : 1325
Book Description
This comprehensive account of the human herpesviruses provides an encyclopedic overview of their basic virology and clinical manifestations. This group of viruses includes human simplex type 1 and 2, Epstein–Barr virus, Kaposi's Sarcoma-associated herpesvirus, cytomegalovirus, HHV6A, 6B and 7, and varicella-zoster virus. The viral diseases and cancers they cause are significant and often recurrent. Their prevalence in the developed world accounts for a major burden of disease, and as a result there is a great deal of research into the pathophysiology of infection and immunobiology. Another important area covered within this volume concerns antiviral therapy and the development of vaccines. All these aspects are covered in depth, both scientifically and in terms of clinical guidelines for patient care. The text is illustrated generously throughout and is fully referenced to the latest research and developments.
Author: Mariano Bizzarri Publisher: Springer Nature ISBN: 3030328570 Category : Medical Languages : en Pages : 493
Book Description
This volume – for pharmacologists, systems biologists, philosophers and historians of medicine – points to investigate new avenues in pharmacology research, by providing a full assessment of the premises underlying a radical shift in the pharmacology paradigm. The pharmaceutical industry is currently facing unparalleled challenges in developing innovative drugs. While drug-developing scientists in the 1990s mostly welcomed the transformation into a target-based approach, two decades of experience shows that this model is failing to boost both drug discovery and efficiency. Selected targets were often not druggable and with poor disease linkage, leading to either high toxicity or poor efficacy. Therefore, a profound rethinking of the current paradigm is needed. Advances in systems biology are revealing a phenotypic robustness and a network structure that strongly suggest that exquisitely selective compounds, compared with multitarget drugs, may exhibit lower than desired clinical efficacy. This appreciation of the role of polypharmacology has significant implications for tackling the two major sources of attrition in drug development, efficacy and toxicity. Integrating network biology and polypharmacology holds the promise of expanding the current opportunity space for druggable targets.
Author: Manja Marz Publisher: MDPI ISBN: 3039218824 Category : Science Languages : en Pages : 330
Book Description
Virus bioinformatics is evolving and succeeding as an area of research in its own right, representing the interface of virology and computer science. Bioinformatic approaches to investigate viral infections and outbreaks have become central to virology research, and have been successfully used to detect, control, and treat infections of humans and animals. As part of the Third Annual Meeting of the European Virus Bioinformatics Center (EVBC), we have published this Special Issue on Virus Bioinformatics.
Author: Decheng Yang Publisher: World Scientific ISBN: 981283379X Category : Medical Languages : en Pages : 722
Book Description
This is the first comprehensive book on human/animal gene responses to RNA viral infections, including prevalent, emerging and re-emerging RNA viruses such as HIV, SARS-CoV, West Nile virus, influenza virus and many others. Human gene responses are reviewed by leading virologists worldwide in the following aspects: (i) the altered gene expression profiles at the transcriptional and translational levels detected with cutting-edge technologies such as cDNA microarray and proteomics; (ii) host innate and adapted immune responses to viral replication in target organs; (iii) virus-activated signal transduction pathways in cell survival, apoptosis and autophagosomal pathways; and (iv) the small interfering RNA/microRNA-mediated gene silencing pathway, a recently characterized new host defense mechanism against viral infection. Organized into 29 highly accessible and well-illustrated chapters, this volume explores state-of-the-art knowledge of the molecular mechanisms of RNA virus infection and host?virus interactions. This comprehensive compilation of the altered gene expression profiles and signal transduction pathways in host cells in response to the majority of human/animal RNA viruses opens new directions for basic and clinical research on viral pathogenesis, and also provides valuable biomarkers for researchers to select gene targets in the development of diagnostic tests and antiviral therapeutics for a number of infectious diseases.
Author: Van G. Wilson Publisher: Springer ISBN: 3319500449 Category : Medical Languages : en Pages : 413
Book Description
This is the second edition of a very well received book that details how the sumoylation system functions and how it modulates numerous cellular activities. SUMO is a post-translational modifier in the ubiquitin super-family that has gained recognition over the last twenty years as an essential and prevalent regulatory molecule. Individual chapters explore the biochemistry, molecular biology, and cell biology of the sumoylation system and its substrate proteins. The book is divided into three themed parts: Molecular Functions (I), Cell Growth Regulation (II), and Diseases (III). Parts I and II focus on the contribution of sumoylation to cellular activities in both the nuclear and cytoplasmic compartments. The nuclear activities covered include nucleic acid metabolism (both RNA and DNA), chromosome structure and replication, and nucleocytoplasmic transport. Cytoplasmic processes presented include regulation of membrane ion channels, general metabolism, and apoptotic signalling. Topics in Part III include the role of sumoylation in developmental abnormalities (craniofacial and cardiovascular), diabetes, neurodegenerative diseases, cancer, and infections with viruses and bacteria. Each of the corresponding chapter authors is an active researcher who has made significant contributions to understanding sumoylation. This second edition provides updates and revisions to most of the original chapters plus adds six new chapters to address important developing areas of sumoylation research. This volume is intended for a scientific audience from undergraduates to independent researchers. The content will serve as both a solid introduction for the novice reader and an in depth treatment for the advanced scholar.
Author: Weidong Yang Publisher: Springer ISBN: 3319773097 Category : Science Languages : en Pages : 277
Book Description
Dysfunction of nuclear-cytoplasmic transport systems has been associated with many human diseases. Thus, understanding of how functional this transport system maintains, or through dysfunction fails to maintain remains the core question in cell biology. In eukaryotic cells, the nuclear envelope (NE) separates the genetic transcription in the nucleus from the translational machinery in the cytoplasm. Thousands of nuclear pore complexes (NPCs) embedded on the NE selectively mediate the bidirectional trafficking of macromolecules such as RNAs and proteins between these two cellular compartments. In this book, the authors integrate recent progress on the structure of NPC and the mechanism of nuclear-cytoplasmic transport system in vitro and in vivo.
Author: Marion Declercq
Author: Chutikarn Chaimayo
Author: Robert G. Webster
Author: Elise Biquand
Author: Ann Arvin
Author: Mariano Bizzarri
Author: Manja Marz
Author: Decheng Yang
Author: Van G. Wilson
Author: Weidong Yang