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1.
Elife ; 112022 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-35801640

RESUMO

Viruses generally are defined as lacking the fundamental properties of living organisms in that they do not harbor an energy metabolism system or protein synthesis machinery. However, the discovery of giant viruses of amoeba has fundamentally challenged this view because of their exceptional genome properties, particle sizes and encoding of the enzyme machinery for some steps of protein synthesis. Although giant viruses are not able to replicate autonomously and still require a host for their multiplication, numerous metabolic genes involved in energy production have been recently detected in giant virus genomes from many environments. These findings have further blurred the boundaries that separate viruses and living organisms. Herein, we summarize information concerning genes and proteins involved in cellular metabolic pathways and their orthologues that have, surprisingly, been discovered in giant viruses. The remarkable diversity of metabolic genes described in giant viruses include genes encoding enzymes involved in glycolysis, gluconeogenesis, tricarboxylic acid cycle, photosynthesis, and ß-oxidation. These viral genes are thought to have been acquired from diverse biological sources through lateral gene transfer early in the evolution of Nucleo-Cytoplasmic Large DNA Viruses, or in some cases more recently. It was assumed that viruses are capable of hijacking host metabolic networks. But the giant virus auxiliary metabolic genes also may represent another form of host metabolism manipulation, by expanding the catalytic capabilities of the host cells especially in harsh environments, providing the infected host cells with a selective evolutionary advantage compared to non-infected cells and hence favoring the viral replication. However, the mechanism of these genes' functionality remains unclear to date.


Assuntos
Amoeba , Vírus Gigantes , Vírus , Vírus de DNA/genética , Genoma Viral , Vírus Gigantes/genética , Filogenia , Vírus/genética
2.
Methods Mol Biol ; 2509: 293-313, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35796971

RESUMO

The transfer of genetic material between viruses and eukaryotic cells is pervasive. Somatic integrations of DNA viruses and retroviruses have been linked to persistent viral infection and genotoxic effects. Integrations into germline cells, referred to as Endogenous Viral Elements (EVEs), can be co-opted for host functions. Besides DNA viruses and retroviruses, EVEs can also derive from nonretroviral RNA viruses, which have often been observed in piRNA clusters. Here, we describe a bioinformatic framework to annotate EVEs in a genome assembly, study their widespread occurrence and polymorphism and identify sample-specific viral integrations using whole genome sequencing data.


Assuntos
Vírus de RNA , Vírus , Vírus de DNA/genética , Vírus de RNA/genética , RNA Interferente Pequeno/genética , Integração Viral , Vírus/genética
3.
Viruses ; 14(7)2022 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-35891423

RESUMO

Ascoviruses are large DNA viruses that primarily infect lepidopteran larvae. They differ markedly from other plant or animal viruses by initiating replication in the nucleus, then inducing nuclear lysis followed by extensive cellular hypertrophy and subsequent cleavage of the entire enlarged cell into numerous viral vesicles. Most progeny virions are assembled in these vesicles as they circulate in the hemolymph. Here, we report transcriptome studies of host cytoskeletal genes in larvae infected with ascoviruses from 6 h to 21 days post-infection (dpi). We focused on the cabbage looper, Trichoplusia ni, infected with the Trichoplusia ni ascovirus (TnAV), along with supporting studies on the fall armyworm, Spodoptera frugiperda, infected with the Spodoptera frugiperda ascovirus (SfAV). In T. ni, many cytoskeleton genes were upregulated at 48 hours post-infection (hpi), including 29 tubulins, 21 actins, 21 dyneins, and 13 kinesins. Mitochondrial genes were upregulated as much as two-fold at 48 hpi and were expressed at levels comparable to controls in both T. ni and S. frugiperda, even after 21 dpi, when several cytoskeleton genes remained upregulated. Our studies suggest a temporal correlation between increases in the expression of certain host cytoskeletal genes and viral vesicle formation. However, these results need confirmation through functional genetic studies of proteins encoded by these genes.


Assuntos
Ascoviridae , Animais , Ascoviridae/genética , Ascoviridae/metabolismo , Citoesqueleto , Vírus de DNA/genética , Larva , Spodoptera , Transcriptoma
4.
Viruses ; 14(7)2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35891454

RESUMO

Putative replication-associated protein (REP) and capsid-like (CAP) proteins are encoded by circular single-stranded DNA viruses (CRESS DNA), which have been found in samples from most eukaryotic groups. However, the details of these viruses' life cycles and their significance in diseases have yet to be established. We presented and analyzed two full-length CRESS DNA genomes acquired from two children diagnosed with acute gastroenteritis (GI) in the northeast state of Tocantins, Brazil, using next-generation sequencing and a virus-like filtration approach. Both sequences (named SmaCV3BR08 and SmaCV3BR291) are closely similar to a prior CRESS DNA sequence discovered in the feces of a new world monkey (Alouatta caraya) from the United States in 2009 and termed Howler monkey-associated porprismacovirus 1 (Genbank ID: NC 026317). According to our comparative study, these porprismacovirus genomes deviate by 10% at the nucleotide level. For comparative reasons, the divergence between our sequences (SmaCV3BR08 and SmaCV3BR291) and a porprismacovirus recently identified in a human fecal sample from Peru is 37%. These data suggest that there is a great diversity of porprismacoviruses in South America, perhaps more than two species. In addition, the finding of closely related sequences of porprismacoviruses in humans and native monkeys highlights the zoonotic potential of these viruses.


Assuntos
Alouatta , Gastroenterite , Alouatta/genética , Animais , Brasil , Criança , Vírus de DNA/genética , DNA Circular , DNA de Cadeia Simples , Gastroenterite/diagnóstico , Gastroenterite/genética , Genoma Viral , Humanos , Filogenia
5.
Viruses ; 14(6)2022 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-35746625

RESUMO

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry worldwide. In Korea, Fostera PRRS commercial modified live virus (MLV) vaccines have been used since 2014 to control the PRRSV infection. In this study, two PRRSV-2 strains (20D160-1 and 21R2-63-1) were successfully isolated, and their complete genomic sequences were determined. Genetic analysis showed that the two isolates have recombination events between the P129-like strain derived from the Fostera PRRS MLV vaccine and the strain of lineage 1. The 20D160-1 indicated that partial ORF2 to partial ORF4 of the minor parental KNU-1902-like strain, which belongs to Korean lineage C (Kor C) of lineage 1, was inserted into the major parental P129-like strain. The 21R2-63-1 revealed that partial ORF1b of the P129-like strain was inserted into the backbone of the NADC30-like strain. This study is the first to report natural recombinant strains between Fostera PRRS MLV-like strain and the field strain in Korea. These results may have significant implications for MLV evolution and the understanding of PRRSV genetic diversity, while highlighting the need for continuous surveillance of PRRSV.


Assuntos
Síndrome Respiratória e Reprodutiva Suína , Vírus da Síndrome Respiratória e Reprodutiva Suína , Vacinas Virais , Vírus não Classificados , Animais , Vírus de DNA , Filogenia , Vírus da Síndrome Respiratória e Reprodutiva Suína/genética , Recombinação Genética , Suínos , Vacinas Atenuadas , Vacinas Virais/genética
6.
Viruses ; 14(6)2022 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-35746646

RESUMO

Knowledge of how congenital Zika syndrome (CZS) impacts motor development of children longitudinally is important to guide management. The objective of the present study was to describe the evolution of gross motor function in children with CZS in a Rio de Janeiro hospital. In children with CZS without arthrogryposis or other congenital osteoarticular malformations who were followed in a prospective cohort study, motor performance was evaluated at two timepoints using the Gross Motor Function Classification System (GMFCS) and the Gross Motor Function Measurement test (GMFM-88). Among 74 children, at the baseline evaluation, the median age was 13 (8-24) months, and on follow-up, 28 (24-48) months. According to GMFCS at the second timepoint, 6 children were classified as mild, 11 as moderate, and 57 as severe. In the GMFM-88 assessment, children in the severe group had a median score of 10.05 in the baseline evaluation and a follow-up score of 12.40, the moderate group had median scores of 25.60 and 29.60, and the mild group had median scores of 82.60 and 91.00, respectively. Although a small developmental improvement was observed, the motor impairment of children was mainly consistent with severe cerebral palsy. Baseline motor function assessments were predictive of prognosis.


Assuntos
Vírus não Classificados , Infecção por Zika virus , Zika virus , Adolescente , Brasil/epidemiologia , Criança , Estudos de Coortes , Vírus de DNA , Seguimentos , Humanos , Lactente , Estudos Prospectivos , Infecção por Zika virus/congênito
7.
Viruses ; 14(6)2022 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-35746655

RESUMO

Bunyaviruses cause diseases in vertebrates, arthropods, and plants. Here, we used high-throughput RNA-seq to identify a bunya-like virus in rice plants showing the dwarfing symptom, which was tentatively named rice dwarf-associated bunya-like virus (RDaBV). The RDaBV genome consists of L, M, and S segments. The L segment has 6562 nt, and encodes an RdRp with a conserved Bunya_RdRp super family domain. The M segment has 1667 nt and encodes a nonstructural protein (NS). The complementary strand of the 1120 nt S segment encodes a nucleocapsid protein (N), while its viral strand encodes a small nonstructural protein (NSs). The amino acid (aa) sequence identities of RdRp, NS, and N between RDaBV and viruses from the family Discoviridae were the highest. Surprisingly, the RDaBV NSs protein did not match any viral proteins. Phylogenetic analysis based on RdRp indicated that RDaBV is evolutionarily close to viruses in the family Discoviridae. The PVX-expressed system indicated that RDaBV N and NS may be symptom determinants of RDaBV. Our movement complementation and callose staining experiment results confirmed that RDaBV NSs is a viral movement protein in plants, while an agro-infiltration experiment found that RDaBV NS is an RNA silencing suppressor. Thus, we determined that RDaBV is a novel rice-infecting bunya-like virus.


Assuntos
Bunyaviridae , Oryza , Vírus não Classificados , Animais , Bunyaviridae/genética , Vírus de DNA/genética , Genoma Viral , Genômica , Oryza/genética , Filogenia , RNA Viral/genética , RNA Polimerase Dependente de RNA , Reoviridae , Proteínas Virais/química , Proteínas Virais/genética , Vírus não Classificados/genética
8.
Viruses ; 14(6)2022 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-35746749

RESUMO

Ecological and experimental infection studies have identified Egyptian rousette bats (ERBs; Rousettus aegyptiacus: family Pteropodidae) as a reservoir host for the zoonotic rubula-like paramyxovirus Sosuga virus (SOSV). A serial sacrifice study of colony-bred ERBs inoculated with wild-type, recombinant SOSV identified small intestines and salivary gland as major sites of viral replication. In the current study, archived formalin-fixed paraffin-embedded (FFPE) tissues from the serial sacrifice study were analyzed in depth-histologically and immunohistochemically, for SOSV, mononuclear phagocytes and T cells. Histopathologic lesion scores increased over time and viral antigen persisted in a subset of tissues, indicating ongoing host responses and underscoring the possibility of chronic infection. Despite the presence of SOSV NP antigen and villus ulcerations in the small intestines, there were only mild increases in mononuclear phagocytes and T cells, a host response aligned with disease tolerance. In contrast, there was a statistically significant, robust and targeted mononuclear phagocyte cell responses in the salivary glands at 21 DPI, where viral antigen was sparse. These findings may have broader implications for chiropteran-paramyxovirus interactions, as bats are hypothesized to be the ancestral hosts of this diverse virus family and for ERB immunology in general, as this species is also the reservoir host for the marburgviruses Marburg virus (MARV) and Ravn virus (RAVV) (family Filoviridae).


Assuntos
Quirópteros , Marburgvirus , Paramyxovirinae , Vírus não Classificados , Animais , Antígenos Virais , Vírus de DNA , Marburgvirus/fisiologia , Tropismo
9.
Viruses ; 14(6)2022 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-35746792

RESUMO

Alfalfa is an important perennial forage crop in Idaho supporting dairy and cattle industries that is typically grown in the same field for as many as 4 years. Alfalfa stands of different ages were subjected to screening for viruses using high-throughput sequencing and RT-PCR. The two most common viruses found were alfalfa mosaic virus and bean leafroll virus, along with Medicago sativa amalgavirus, two alphapartitiviruses, and one deltapartitivirus. Additionally, a new flavi-like virus with an unusual genome organization was discovered, dubbed Snake River alfalfa virus (SRAV). The 11,745 nt, positive-sense (+) RNA genome of SRAV encodes a single 3835 aa polyprotein with only two identifiable conserved domains, an RNA-dependent RNA polymerase (RdRP) and a predicted serine protease. Notably, unlike all +RNA virus genomes in the similar size range, the SRAV polyprotein contained no predicted helicase domain. In the RdRP phylogeny, SRAV was placed inside the flavi-like lineage as a sister clade to a branch consisting of hepaci-, and pegiviruses. To the best of our knowledge, SRAV is the first flavi-like virus identified in a plant host. Although commonly detected in alfalfa crops in southern Idaho, SRAV sequences were also amplified from thrips feeding in alfalfa stands in the area, suggesting a possible role of Frankliniella occidentalis in virus transmission.


Assuntos
Vírus de RNA , Vírus não Classificados , Animais , Bovinos , Produtos Agrícolas/genética , Vírus de DNA/genética , Medicago sativa , Poliproteínas , RNA , Vírus de RNA/genética , RNA Polimerase Dependente de RNA , Rios , Vírus não Classificados/genética
10.
Antiviral Res ; 203: 105347, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35643150

RESUMO

Zika virus (ZIKV) is a flavivirus that causes severe neuropathology in newborns and adults. There is no ZIKV-specific treatment or preventative. Therefore, it is urgent to develop safe and effective anti-ZIKV agents. Hemin, an iron-binding porphyrin, has been authorized by FDA to treat acute porphyria since the 1970s. Here, we aim to evaluate the anti-ZIKV effect of hemin in SNB-19 cells (a human glioma cell line) and explore the underlying mechanism based on the virus life cycle and functions of the host cell. Our study found that hemin has a strong activity to protect SNB-19 cells from ZIKV infection presented by decreased expression of viral proteins and virus yield. Meanwhile, ZIKV infection caused STAT1/IRF1 signaling activation and induced inflammatory responses in SNB-19 cells, which was relieved by hemin treatment. HO-1 has been reported to be potently induced by hemin and play a broad-spectrum antiviral effect. Intriguingly, hemin could still exert anti-ZIKV activity upon HO-1 siRNA treatment. Then, we conducted a time-of-addition assay, the result indicated hemin works mainly by interfering with the virus entry process. Further experiments excluded the effects of hemin on AXL-dependent viral adsorption and clathrin-mediated endocytosis processes. Subsequently, by fluorescence spectroscopy studies, intracellular fusion assay and syncytia formation assay, we revealed that hemin acts on the process of virus-endosome fusion. This study elaborated that hemin could play anti-ZIKV activity by disrupting the virus-endosome fusion process and shed new light on developing novel agents against ZIKV infection.


Assuntos
Infecção por Zika virus , Zika virus , Animais , Chlorocebus aethiops , Vírus de DNA , Endossomos , Hemina/farmacologia , Humanos , Recém-Nascido , Células Vero , Internalização do Vírus , Replicação Viral , Infecção por Zika virus/metabolismo
11.
Sci Rep ; 12(1): 9109, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35650235

RESUMO

The COVID-19 pandemic has caused a multi-scale impact on the world population that started from a nano-scale respiratory virus and led to the shutdown of macro-scale economies. Direct transmission of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) and its variants through aerosolized droplets is a major contributor towards increasing cases of this infection. To curb the spread, one of the best engineered solutions is the use of face masks to prevent the passage of infectious saliva micro-droplets from an infected person to a healthy person. The commercially available masks are single use, passive face-piece filters. These become difficult to breathe in during strenuous activities. Also, they need to be disposed regularly due to accumulation of unwanted particulate and pathogens over time. Frequent disposal of these masks is unsustainable for the environment. In this study, we have proposed a novel design for a filter for enhanced virus filtration, better breathability, and virus inactivation over time. The filter is called Hy-Cu named after its (Hy) drophobic properties and another significant layer comprises of copper (Cu). The breathability (pressure drop across filter) of Hy-Cu is tested and compared with widely used surgical masks and KN95 masks, both experimentally and numerically. The results show that the Hy-Cu filter offers at least 10% less air resistance as compared to commercially available masks. The experimental results on virus filtration and inactivation tests using MS2 bacteriophage (a similar protein structure as SARS-CoV-2) show that the novel filter has 90% filtering efficiency and 99% virus inactivation over a period of 2 h. This makes the Hy-Cu filter reusable and a judicious substitute to the single use masks.


Assuntos
COVID-19 , Pandemias , COVID-19/prevenção & controle , Vírus de DNA , Filtração , Humanos , Levivirus , SARS-CoV-2
12.
Emerg Infect Dis ; 28(7): 1480-1484, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35731188

RESUMO

We isolated a novel reassortant influenza A(H10N7) virus from a harbor seal in British Columbia, Canada, that died from bronchointerstitial pneumonia. The virus had unique genome constellations involving lineages from North America and Eurasia and polymerase basic 2 segment D701N mutation, associated with adaptation to mammals.


Assuntos
Vírus da Influenza A Subtipo H10N7 , Influenza Aviária , Influenza Humana , Infecções por Orthomyxoviridae , Phoca , Animais , Colúmbia Britânica/epidemiologia , Vírus de DNA , Humanos , Vírus da Influenza A Subtipo H10N7/genética , Influenza Humana/epidemiologia , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/veterinária , Filogenia , Vírus Reordenados/genética
13.
Int J Mol Sci ; 23(11)2022 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-35682986

RESUMO

In this study, a series of 4-[(quinolin-4-yl)amino]benzamide derivatives as the novel anti-influenza agents were designed and synthesized. Cytotoxicity assay, cytopathic effect assay and plaque inhibition assay were performed to evaluate the anti-influenza virus A/WSN/33 (H1N1) activity of the target compounds. The target compound G07 demonstrated significant anti-influenza virus A/WSN/33 (H1N1) activity both in cytopathic effect assay (EC50 = 11.38 ± 1.89 µM) and plaque inhibition assay (IC50 = 0.23 ± 0.15 µM). G07 also exhibited significant anti-influenza virus activities against other three different influenza virus strains A/PR/8 (H1N1), A/HK/68 (H3N2) and influenza B virus. According to the result of ribonucleoprotein reconstitution assay, G07 could interact well with ribonucleoprotein with an inhibition rate of 80.65% at 100 µM. Furthermore, G07 exhibited significant activity target PA-PB1 subunit of RNA polymerase according to the PA-PB1 inhibitory activity prediction by the best pharmacophore Hypo1. In addition, G07 was well drug-likeness based on the results of Lipinski's rule and ADMET prediction. All the results proved that 4-[(quinolin-4-yl)amino]benzamide derivatives could generate potential candidates in discovery of anti-influenza virus agents.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Vírus da Influenza A Subtipo H3N2 , Antivirais/farmacologia , Benzamidas/farmacologia , Vírus de DNA , Simulação de Acoplamento Molecular , Ribonucleoproteínas , Replicação Viral
14.
Viruses ; 14(6)2022 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-35746816

RESUMO

Viruses can infect members of all three domains of life. However, little is known about viruses infecting archaea and the mechanisms that determine their host interactions are poorly understood. Investigations of molecular mechanisms of viral infection rely on genetically accessible virus-host model systems. Euryarchaea belonging to the genus Haloferax are interesting models, as a reliable genetic system and versatile microscopy methods are available. However, only one virus infecting the Haloferax species is currently available. In this study, we tested ~100 haloarchaeal virus isolates for their infectivity on 14 Haloferax strains. From this, we identified 10 virus isolates in total capable of infecting Haloferax strains, which represented myovirus or siphovirus morphotypes. Surprisingly, the only susceptible strain of all 14 tested was Haloferax gibbonsii LR2-5, which serves as an auspicious host for all of these 10 viruses. By applying comparative genomics, we shed light on factors determining the host range of haloarchaeal viruses on Haloferax. We anticipate our study to be a starting point in the study of haloarchaeal virus-host interactions.


Assuntos
Haloferax , Archaea , Vírus de DNA , Genômica , Haloferax/genética , Especificidade de Hospedeiro
15.
BMC Bioinformatics ; 23(1): 196, 2022 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-35643449

RESUMO

BACKGROUND: SARS-CoV-2 is the highly transmissible etiologic agent of coronavirus disease 2019 (COVID-19) and has become a global scientific and public health challenge since December 2019. Several new variants of SARS-CoV-2 have emerged globally raising concern about prevention and treatment of COVID-19. Early detection and in-depth analysis of the emerging variants allowing pre-emptive alert and mitigation efforts are thus of paramount importance. RESULTS: Here we present ClusTRace, a novel bioinformatic pipeline for a fast and scalable analysis of sequence clusters or clades in large viral phylogenies. ClusTRace offers several high-level functionalities including lineage assignment, outlier filtering, aligning, phylogenetic tree reconstruction, cluster extraction, variant calling, visualization and reporting. ClusTRace was developed as an aid for COVID-19 transmission chain tracing in Finland with the main emphasis on fast screening of phylogenies for markers of super-spreading events and other features of concern, such as high rates of cluster growth and/or accumulation of novel mutations. CONCLUSIONS: ClusTRace provides an effective interface that can significantly cut down learning and operating costs related to complex bioinformatic analysis of large viral sequence sets and phylogenies. All code is freely available from https://bitbucket.org/plyusnin/clustrace/.


Assuntos
COVID-19 , Biologia Computacional , Vírus de DNA , Humanos , Filogenia , SARS-CoV-2/genética
16.
PLoS Pathog ; 18(6): e1010589, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35666744

RESUMO

Non-coding regions of viral RNA (vRNA) genomes are critically important in the regulation of gene expression. In particular, pseudoknot (PK) structures, which are present in a wide range of RNA molecules, have a variety of roles. The 5' untranslated region (5' UTR) of foot-and-mouth disease virus (FMDV) vRNA is considerably longer than in other viruses from the picornavirus family and consists of a number of distinctive structural motifs that includes multiple (2, 3 or 4 depending on the virus strain) putative PKs linked in tandem. The role(s) of the PKs in the FMDV infection are not fully understood. Here, using bioinformatics, sub-genomic replicons and recombinant viruses we have investigated the structural conservation and importance of the PKs in the FMDV lifecycle. Our results show that despite the conservation of two or more PKs across all FMDVs, a replicon lacking PKs was replication competent, albeit at reduced levels. Furthermore, in competition experiments, GFP FMDV replicons with less than two (0 or 1) PK structures were outcompeted by a mCherry FMDV wt replicon that had 4 PKs, whereas GFP replicons with 2 or 4 PKs were not. This apparent replicative advantage offered by the additional PKs correlates with the maintenance of at least two PKs in the genomes of FMDV field isolates. Despite a replicon lacking any PKs retaining the ability to replicate, viruses completely lacking PK were not viable and at least one PK was essential for recovery of infections virus, suggesting a role for the PKs in virion assembly. Thus, our study points to roles for the PKs in both vRNA replication and virion assembly, thereby improving understanding the molecular biology of FMDV replication and the wider roles of PK in RNA functions.


Assuntos
Vírus da Febre Aftosa , Febre Aftosa , Regiões 5' não Traduzidas , Animais , Vírus de DNA , Febre Aftosa/genética , Vírus da Febre Aftosa/genética , Genoma Viral , RNA Viral/química , Replicação Viral/genética
17.
PLoS Pathog ; 18(6): e1010553, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35653397

RESUMO

Nelson Bay orthoreovirus (NBV), a member of the family Reoviridae, genus Orthoreovirus, is a bat-borne virus that causes respiratory diseases in humans. NBV encodes two unique nonstructural proteins, fusion-associated small transmembrane (FAST) protein and p17 protein, in the S1 gene segment. FAST induces cell-cell fusion between infected cells and neighboring cells and the fusogenic activity is required for efficient viral replication. However, the function of p17 in the virus cycle is not fully understood. Here, various p17 mutant viruses including p17-deficient viruses were generated by a reverse genetics system for NBV. The results demonstrated that p17 is not essential for viral replication and does not play an important role in viral pathogenesis. On the other hand, NBV p17 regulated viral replication in a bat cell line but not in other human and animal cell lines. Nuclear localization of p17 is associated with the regulation of NBV replication in bat cells. We also found that p17 dramatically enhances the cell-cell fusion activity of NBV FAST protein for efficient replication in bat cells. Furthermore, we found that a protein homologue of NBV p17 from another bat-borne orthoreovirus, but not those of avian orthoreovirus or baboon orthoreovirus, also supported efficient viral replication in bat cells using a p17-deficient virus-based complementation approach. These results provide critical insights into the functioning of the unique replication machinery of bat-borne viruses in their natural hosts.


Assuntos
Quirópteros , Orthoreovirus , Reoviridae , Animais , Anticorpos Antivirais , Vírus de DNA , Orthoreovirus/genética , Replicação Viral
18.
Front Immunol ; 13: 889736, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35655779

RESUMO

During the pre-vaccine era of the COVID-19 pandemic convalescent plasma has once again emerged as a major potential therapeutic form of passive immunization that in specific cases still represents irreplaceable treatment option. There is a growing concern that variable concentration of neutralizing antibodies, present in convalescent plasma which originates from different donors, apparently affects its effectiveness. The drawback can be overcome through the downstream process of immunoglobulin fraction purification into a standardized product of improved safety and efficacy. All modern procedures are quite lengthy processes. They are also based on fractionation of large plasma quantities whose collection is not attainable during an epidemic. When outbreaks of infectious diseases are occurring more frequently, there is a great need for a more sustainable production approach that would be goal-oriented towards assuring easily and readily available immunoglobulin of therapeutic relevance. We propose a refinement strategy for the IgG preparation achieved through simplification and reduction of the processing steps. It was designed as a small but scalable process to offer an immediately available treatment option that would simultaneously be harmonized with an increased availability of convalescent plasma over the viral outbreak time-course. Concerning the ongoing pandemic status of the COVID-19, the proof of concept was demonstrated on anti-SARS-CoV-2 convalescent plasma but is likely applicable to any other type depending on the current needs. It was guided by the idea of persistent keeping of IgG molecules in the solution, so that protection of their native structure could be assured. Our manufacturing procedure provided a high-quality IgG product of above the average recovery whose composition profile was analyzed by mass spectrometry as quality control check. It was proved free from IgA and IgM as mediators of adverse transfusion reactions, as well as of any other residual impurities, since only IgG fragments were identified. The proportion of S protein-specific IgGs remained unchanged relative to the convalescent plasma. Undisturbed IgG subclass composition was accomplished as well. However, the fractionation principle affected the final product's capacity to neutralize wild-type SARS-CoV-2 infectivity, reducing it by half. Decrease in neutralization potency significantly correlated with the amount of IgM in the starting material.


Assuntos
COVID-19 , Imunoglobulina G , COVID-19/epidemiologia , COVID-19/terapia , Vírus de DNA , Humanos , Imunização Passiva , Imunoglobulina M , Pandemias , SARS-CoV-2
19.
Cell Rep ; 39(10): 110920, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35675783

RESUMO

Retinoic acid-inducible-I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and cyclic GMP-AMP synthase (cGAS) genes encode essential cytosolic receptors mediating antiviral immunity against viruses. Here, we show that OTUD3 has opposing role in response to RNA and DNA virus infection by removing distinct types of RIG-I/MDA5 and cGAS polyubiquitination. OTUD3 binds to RIG-I and MDA5 and removes K63-linked ubiquitination. This serves to reduce the binding of RIG-I and MDA5 to viral RNA and the downstream adaptor MAVS, leading to the suppression of the RNA virus-triggered innate antiviral responses. Meanwhile, OTUD3 associates with cGAS and targets at Lys279 to deubiquitinate K48-linked ubiquitination, resulting in the enhancement of cGAS protein stability and DNA-binding ability. As a result, Otud3-deficient mice and zebrafish are more resistant to RNA virus infection but are more susceptible to DNA virus infection. These findings demonstrate that OTUD3 limits RNA virus-triggered innate immunity but promotes DNA virus-triggered innate immunity.


Assuntos
Infecções por Vírus de DNA , Imunidade Inata , Infecções por Vírus de RNA , Proteases Específicas de Ubiquitina , Animais , Proteína DEAD-box 58/metabolismo , Infecções por Vírus de DNA/imunologia , Vírus de DNA , Enzimas Desubiquitinantes , Helicase IFIH1 Induzida por Interferon/metabolismo , Camundongos , Nucleotidiltransferases , Infecções por Vírus de RNA/imunologia , Vírus de RNA , RNA Viral/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Peixe-Zebra/metabolismo
20.
Cell Rep ; 39(12): 110976, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35732126

RESUMO

dsRNA sensing triggers antiviral responses against RNA and DNA viruses in diverse eukaryotes. In Drosophila, Invertebrate iridescent virus 6 (IIV-6), a large DNA virus, triggers production of small interfering RNAs (siRNAs) by the dsRNA sensor Dicer-2. Here, we show that host RNA polymerase II (RNAPII) bidirectionally transcribes specific AT-rich regions of the IIV-6 DNA genome to generate dsRNA. Both replicative and naked IIV-6 genomes trigger production of dsRNA in Drosophila cells, implying direct sensing of invading DNA. Loquacious-PD, a Dicer-2 co-factor essential for the biogenesis of endogenous siRNAs, is dispensable for processing of IIV-6-derived dsRNAs, which suggests that they are distinct. Consistent with this finding, inhibition of the RNAPII co-factor P-TEFb affects the synthesis of endogenous, but not virus-derived, dsRNA. Altogether, our results suggest that a non-canonical RNAPII complex recognizes invading viral DNA to synthesize virus-derived dsRNA, which activates the antiviral siRNA pathway in Drosophila.


Assuntos
DNA Viral , Drosophila , Animais , Antivirais , Vírus de DNA/genética , Drosophila/metabolismo , Iridovirus , Interferência de RNA , RNA Polimerase II/metabolismo , RNA de Cadeia Dupla/genética , RNA Interferente Pequeno/metabolismo , RNA Viral/metabolismo
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