Architecture of ribonucleoprotein complexes in influenza A virus particles

Nature ◽  
2006 ◽  
Vol 439 (7075) ◽  
pp. 490-492 ◽  
Author(s):  
Takeshi Noda ◽  
Hiroshi Sagara ◽  
Albert Yen ◽  
Ayato Takada ◽  
Hiroshi Kida ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Virus Particles ◽  
Ribonucleoprotein Complexes

Evidence for specific packaging of the influenza A virus genome from conditionally defective virus particles lacking a polymerase gene

Vaccine ◽  
2006 ◽  
Vol 24 (44-46) ◽  
pp. 6647-6650 ◽  
Author(s):  
Emmie de Wit ◽  
Monique I.J. Spronken ◽  
Guus F. Rimmelzwaan ◽  
Albert D.M.E. Osterhaus ◽  
Ron A.M. Fouchier
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Virus Genome ◽  
Polymerase Gene ◽  
Virus Particles ◽  
Defective Virus

scholarly journals Chenodeoxycholic Acid from Bile Inhibits Influenza A Virus Replication via Blocking Nuclear Export of Viral Ribonucleoprotein Complexes

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3315 ◽  
Author(s):  
Ling Luo ◽  
Weili Han ◽  
Jinyan Du ◽  
Xia Yang ◽  
Mubing Duan ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Chenodeoxycholic Acid ◽  
Nuclear Export ◽  
Influenza A ◽  
Antiviral Agent ◽  
Dietary Fats ◽  
Lipid Mediator ◽  
Omega 3 ◽  
Ribonucleoprotein Complexes

Influenza A virus (IAV) infection is still a major global threat for humans, especially for the risk groups: young children and the elderly. The currently licensed antiviral drugs target viral factors and are prone to viral resistance. In recent years, a few endogenous small molecules from host, such as estradiol and omega-3 polyunsaturated fatty acid (PUFA)-derived lipid mediator protection D1 (PD1), were demonstrated to be capable of inhibiting IAV infection. Chenodeoxycholic acid (CDCA), one of the main primary bile acids, is synthesized from cholesterol in the liver and classically functions in emulsification and absorption of dietary fats. Clinically, CDCA has been used in the treatment of patients with cholesterol gallstones for more than five decades. In this study, we showed that CDCA attenuated the replication of three subtypes of influenza A virus, including a highly pathogenic H5N1 strain, in A549 and MDCK cell cultures with IC50 ranging from 5.5 to 11.5 μM. Mechanistically, CDCA effectively restrained the nuclear export of viral ribonucleoprotein (vRNP) complexes. In conclusion, as an endogenous physiological small molecule, CDCA can inhibit IAV replication in vitro, at least in part, by blocking vRNP nuclear export, and affords further studies for development as a potential antiviral agent against IAV infections.

Several protein regions contribute to determine the nuclear and cytoplasmic localization of the influenza A virus nucleoprotein

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Rosario Bullido ◽  
Paulino Gómez-Puertas ◽  
Carmen Albo ◽  
Agustín Portela
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Fluorescent Protein ◽  
Intracellular Localization ◽  
Phosphorylation Site ◽  
Nuclear Accumulation ◽  
Systematic Analysis ◽  
Ribonucleoprotein Complexes ◽  
Cytoplasmic Transport ◽  
Green Fluorescent

A systematic analysis was carried out to identify the amino acid signals that regulate the nucleo-cytoplasmic transport of the influenza A virus nucleoprotein (NP). The analysis involved determining the intracellular localization of eight deleted recombinant NP proteins and 14 chimeric proteins containing the green fluorescent protein fused to different NP fragments. In addition, the subcellular distribution of NP derivatives that contained specific substitutions at serine-3, which is the major phosphorylation site of the A/Victoria/3/75 NP, were analysed. From the results obtained, it is concluded that the NP contains three signals involved in nuclear accumulation and two regions that cause cytoplasmic accumulation of the fusion proteins. One of the karyophilic signals was located at the N terminus of the protein, and the data obtained suggest that the functionality of this signal can be modified by phosphorylation at serine-3. These findings are discussed in the context of the transport of influenza virus ribonucleoprotein complexes into and out of the nucleus.

scholarly journals The Influenza A Virus M2 Cytoplasmic Tail Is Required for Infectious Virus Production and Efficient Genome Packaging

2005 ◽  
Vol 79 (6) ◽  
pp. 3595-3605 ◽  
Author(s):  
Matthew F. McCown ◽  
Andrew Pekosz
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Infectious Virus ◽  
Virus Production ◽  
Cytoplasmic Tail ◽  
Host Cells ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Virus Particles

ABSTRACT The M2 integral membrane protein encoded by influenza A virus possesses an ion channel activity that is required for efficient virus entry into host cells. The role of the M2 protein cytoplasmic tail in virus replication was examined by generating influenza A viruses encoding M2 proteins with truncated C termini. Deletion of 28 amino acids (M2Stop70) resulted in a virus that produced fourfold-fewer particles but >1,000-fold-fewer infectious particles than wild-type virus. Expression of the full-length M2 protein in trans restored the replication of the M2 truncated virus. Although the M2Stop70 virus particles were similar to wild-type virus in morphology, the M2Stop70 virions contained reduced amounts of viral nucleoprotein and genomic RNA, indicating a defect in vRNP packaging. The data presented indicate the M2 cytoplasmic tail plays a role in infectious virus production by coordinating the efficient packaging of genome segments into influenza virus particles.

scholarly journals THE PRODUCTION OF FEVER BY INFLUENZAL VIRUSES

1949 ◽  
Vol 90 (4) ◽  
pp. 321-334 ◽  
Author(s):  
Robert R. Wagner ◽  
Ivan L. Bennett ◽  
Virgil S. LeQuire
Keyword(s):  
Influenza A Virus ◽  
Low Temperatures ◽  
Influenza A ◽  
Immune Serum ◽  
Influenza B ◽  
Chick Embryos ◽  
Febrile Response ◽  
Virus Particles ◽  
Chicken Erythrocytes

The intravenous injection of the PR8 strain of influenza A virus, the Lee strain of influenza B, and the "B" strain of Newcastle disease virus produces fever in rabbits. This phenomenon has been studied in relation to certain in vitro properties of these viruses. Saline suspensions of virus prepared by centrifugation or elution from chicken erythrocytes produced fever. Fluids from which most of the virus particles had been removed were non-pyrogenic. Exposure to temperatures which destroyed the infectivity of the virus for chick embryos did not prevent fever. However, heating sufficient to destroy the hemagglutinin also rendered virus non-pyrogenic. The injection of erythrocytes onto which virus had been adsorbed produced fever. Heated virus adsorbed onto erythrocytes, which failed to elute, produced no elevation of temperature, although heated virus alone was pyrogenic. Neutralization of virus with specific immune serum prevented fever. Antipyrine was capable of abolishing the febrile response to virus. Certain differences between the febrile response in rabbits to the injection of viruses and that following bacterial pyrogens were noted. The period between injection and beginning of temperature rise is longer with virus than with bacterial pyrogens. Relatively low temperatures inactivate the fever-producing capacity of viruses, whereas bacterial pyrogens withstand prolonged autoclaving, and the neutralization of viral fever by specific immune serum contrasts sharply with the failure of antibody to affect the response to bacterial pyrogens. Certain previous observations on the lymphopenia produced in rabbits by the injection of influenzal viruses were confirmed. The capacity of virus preparations to induce fever in rabbits closely parallels their capacity to induce lymphopenia. It was concluded that the fever-producing property of influenzal viruses is closely associated with the capacity to agglutinate erythrocytes.

scholarly journals Distinct Domains of the Influenza A Virus M2 Protein Cytoplasmic Tail Mediate Binding to the M1 Protein and Facilitate Infectious Virus Production

2006 ◽  
Vol 80 (16) ◽  
pp. 8178-8189 ◽  
Author(s):  
Matthew F. McCown ◽  
Andrew Pekosz
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Reverse Genetics ◽  
Infectious Virus ◽  
Virus Assembly ◽  
Virus Production ◽  
Cytoplasmic Tail ◽  
M2 Protein ◽  
Virus Particles ◽  
M1 Protein

ABSTRACT The cytoplasmic tail of the influenza A virus M2 protein is highly conserved among influenza A virus isolates. The cytoplasmic tail appears to be dispensable with respect to the ion channel activity associated with the protein but important for virus morphology and the production of infectious virus particles. Using reverse genetics and transcomplementation assays, we demonstrate that the M2 protein cytoplasmic tail is a crucial mediator of infectious virus production. Truncations of the M2 cytoplasmic tail result in a drastic decrease in infectious virus titers, a reduction in the amount of packaged viral RNA, a decrease in budding events, and a reduction in budding efficiency. The M1 protein binds to the M2 cytoplasmic tail, but the M1 binding site is distinct from the sequences that affect infectious virus particle formation. Influenza A virus strains A/Udorn/72 and A/WSN/33 differ in their requirements for M2 cytoplasmic tail sequences, and this requirement maps to the M1 protein. We conclude that the M2 protein is required for the formation of infectious virus particles, implicating the protein as important for influenza A virus assembly in addition to its well-documented role during virus entry and uncoating.

scholarly journals Cell culture–based production of defective interfering influenza A virus particles in perfusion mode using an alternating tangential flow filtration system

2021 ◽  
Author(s):  
Marc D. Hein ◽  
Anshika Chawla ◽  
Maurizio Cattaneo ◽  
Sascha Y. Kupke ◽  
Yvonne Genzel ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Hollow Fiber ◽  
Influenza A ◽  
Tubular Cell ◽  
Cell Retention ◽  
Virus Particles ◽  
Tangential Flow ◽  
Perfusion Process ◽  
Flow Filtration ◽  
Retention Device

AbstractRespiratory diseases including influenza A virus (IAV) infections represent a major threat to human health. While the development of a vaccine requires a lot of time, a fast countermeasure could be the use of defective interfering particles (DIPs) for antiviral therapy. IAV DIPs are usually characterized by a large internal deletion in one viral RNA segment. Consequentially, DIPs can only propagate in presence of infectious standard viruses (STVs), compensating the missing gene function. Here, they interfere with and suppress the STV replication and might act “universally” against many IAV subtypes. We recently reported a production system for purely clonal DIPs utilizing genetically modified cells. In the present study, we established an automated perfusion process for production of a DIP, called DI244, using an alternating tangential flow filtration (ATF) system for cell retention. Viable cell concentrations and DIP titers more than 10 times higher than for a previously reported batch cultivation were observed. Furthermore, we investigated a novel tubular cell retention device for its potential for continuous virus harvesting into the permeate. Very comparable performances to typically used hollow fiber membranes were found during the cell growth phase. During the virus replication phase, the tubular membrane, in contrast to the hollow fiber membrane, allowed 100% of the produced virus particles to pass through. To our knowledge, this is the first time a continuous virus harvest was shown for a membrane-based perfusion process. Overall, the process established offers interesting possibilities for advanced process integration strategies for next-generation virus particle and virus vector manufacturing.Key points• An automated perfusion process for production of IAV DIPs was established.• DIP titers of 7.40E + 9 plaque forming units per mL were reached.• A novel tubular cell retention device enabled continuous virus harvesting.

scholarly journals The host factor ANP32A is required for influenza A virus vRNA and cRNA synthesis

2021 ◽  
Author(s):  
Benjamin E Nilsson-Payant ◽  
Benjamin R. tenOever ◽  
Aartjan J.W. te Velthuis
Keyword(s):  
Rna Polymerase ◽  
Viral Replication ◽  
Influenza A Virus ◽  
Influenza A ◽  
Host Factor ◽  
Viral Rna ◽  
Molecular Evidence ◽  
Influenza A Viruses ◽  
Ribonucleoprotein Complexes ◽  
Rna Genome

Influenza A viruses are negative-sense RNA viruses that rely on their own viral replication machinery to replicate and transcribe their segmented single-stranded RNA genome. The viral ribonucleoprotein complexes in which viral RNA is replicated consist of a nucleoprotein scaffold around which the RNA genome is bound, and a heterotrimeric RNA-dependent RNA polymerase that catalyzes viral replication. The RNA polymerase copies the viral RNA (vRNA) via a replicative intermediate, called the complementary RNA (cRNA), and subsequently uses this cRNA to make more vRNA copies. To ensure that new cRNA and vRNA molecules are associated with ribonucleoproteins in which they can be amplified, the active RNA polymerase recruits a second polymerase to encapsidate the cRNA or vRNA. Host factor ANP32A has been shown to be essential for viral replication and to facilitate the formation of a dimer between viral RNA polymerases and differences between mammalian and avian ANP32A proteins are sufficient to restrict viral replication. It has been proposed that ANP32A is only required for the synthesis of vRNA molecules from a cRNA, but not vice versa. However, this view does not match recent molecular evidence. Here we use minigenome assays, virus infections, and viral promoter mutations to demonstrate that ANP32A is essential for both vRNA and cRNA synthesis. Moreover, we show that ANP32 is not only needed for the actively replicating polymerase, but also for the polymerase that is encapsidating nascent viral RNA products. Overall, these results provide new insights into influenza A virus replication and host adaptation.

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