Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20.449
Filtrar
1.
Arch Virol ; 165(3): 691-702, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32016546

RESUMO

Here, we present the results of a study in which 639 samples obtained between October 2018 and April 2019 from patients with symptoms of acute gastroenteritis were tested for the presence of a rotavirus infection. The antigen of group A rotavirus was detected in 160 samples (25% of those tested). To study the genetic diversity of group A rotavirus, RNA was isolated from the samples, and polymerase chain reaction combined with reverse transcription (RT-PCR) with primers specific for the VP4, VP6, and VP7 genes of group A rotaviruses was performed. At least one fragment of the group A rotavirus genome was found in 101 samples (15.8%). These fragments were sequenced, and their G and P genotypes-as well as their combinations-were determined. The predominant G genotypes were G9 (35.8% of all genotyped samples) and G4 (28.4%), but the rare G12 genotype was also found (3.0%). The dominant P genotype was P[8]. The spectrum of certain G/P combinations of genotypes included seven variants. The most common variants were G9P[8] (37.2%) and G4P[8] (30.2%).


Assuntos
Variação Genética , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/genética , Adolescente , Adulto , Sequência de Aminoácidos , Criança , Pré-Escolar , Genótipo , Humanos , Lactente , Pessoa de Meia-Idade , Moscou , Filogenia , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo , Adulto Jovem
2.
Arch Virol ; 165(3): 571-582, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32030535

RESUMO

Torque teno virus (TTV), torque teno mini virus (TTMV) and torque teno midi virus (TTMDV) are members of the family Anelloviridae that are known to infect humans. Although no pathogenic roles have been associated with anelloviruses, their high prevalence and perceived ubiquitousness have provoked scientific interest in understanding their molecular and biological characteristics. We used nested PCR to determine the prevalence of anelloviruses among 130 human immunodeficiency virus (HIV)-infected patients and 130 healthy blood donors, and analyzed three near-full-length genome sequences of TTV isolates from HIV-infected and non-HIV infected Nigerians. Statistical analysis showed that the rate of TTV infection was significantly higher in the HIV-infected group (65%) than in the blood donor group (26%) (p < 0.05, χ2 = 40.3). TTMV and TTMDV infections were very high in both groups, ranging between 88 and 95%. No significant association was found between TTV infection and age, sex, CD4+ cell count, HIV viral load or alanine aminotransferase (ALT) level. Near-full-length genome sequences of TTV isolates FL100, FL08 and BD67 determined by next-generation sequencing were 3.6 kb, 3.2 kb and 2.9 kb, respectively, in size. Their GenBank accession numbers are MK820644, MK820645, MK820646, respectively. These isolates shared 59% sequence identity across the whole genome and clustered in two different phylogenetic groups. Our study established for the first time the circulation of TTV, TTMV and TTMDV in the Nigerian population, with a disproportionately higher prevalence of TTV in HIV-infected patients. The near-complete TTV genome sequences from Nigeria are similar to the sequences KT163879 and KT163916 (3748 and 3190 respectively), obtained from the plasma of HIV-infected subjects from the United States, and EU305675 (2919), identified in human plasma samples from France.


Assuntos
Infecções por Vírus de DNA/complicações , Infecções por Vírus de DNA/virologia , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Torque teno virus/isolamento & purificação , Sequência de Aminoácidos , Contagem de Linfócito CD4 , Infecções por Vírus de DNA/epidemiologia , HIV-1 , Humanos , Nigéria/epidemiologia , Filogenia , Torque teno virus/classificação , Carga Viral , Proteínas Virais/química , Proteínas Virais/metabolismo
3.
Arch Virol ; 165(3): 557-570, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32036428

RESUMO

Codon usage bias (CUB) arises from the preference for a codon over codons for the same amino acid. The major factors contributing to CUB are evolutionary forces, compositional properties, gene expression, and protein properties. The present analysis was performed to investigate the compositional properties and the extent of CUB across the genomes of members of the family Hepadnaviridae, as previously no work using bioinformatic tools has been reported. The viral genes were found to be AT rich with low CUB. Analysis of relative synonymous codon usage (RSCU) was used to identify overrepresented and underrepresented codons for each amino acid. Correlation analysis of overall nucleotide composition and its composition at the third codon position suggested that mutation pressure might influence the CUB. A highly significant correlation was observed between GC12 and GC3 (r = 0.910, p < 0.01), indicating that directional mutation affected all three codon positions across the genome. Translational selection (P2) and mutational responsive index (MRI) values of genes suggested that mutation plays a more important role than translational selection in members of the family Hepadnaviridae.


Assuntos
Regulação Viral da Expressão Gênica/fisiologia , Genoma Viral/fisiologia , Hepadnaviridae/metabolismo , Proteínas Virais/metabolismo , Evolução Biológica , Hepadnaviridae/genética , Mutação , RNA Mensageiro , RNA Viral , Especificidade da Espécie , Proteínas Virais/genética
4.
Arch Virol ; 165(3): 785-788, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31980938

RESUMO

In this study, the complete genomic sequence of a novel botoulivirus (Sclerotinia minor botoulivirus 1, SmBV1) from the phytopathogenic fungus Sclerotinia minor strain LC45 was determined. The genome of SmBV1 is 2,882 nucleotides in length and contains a single large open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp). Phylogenetic analysis showed that SmBV1 clustered with the botoulivirus clade within the family Botourmiaviridae. This is the first report of a botoulivirus in S. minor.


Assuntos
Ascomicetos/virologia , Micovírus/isolamento & purificação , Micovírus/fisiologia , Sequência de Aminoácidos , Micovírus/genética , Filogenia , Proteínas Virais/genética , Proteínas Virais/metabolismo
5.
Arch Virol ; 165(1): 69-85, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31705208

RESUMO

Herpesviruses are predicted to express more than 80 proteins during their infection cycle. The proteins synthesized by the immediate early genes and early genes target signaling pathways in host cells that are essential for the successful initiation of a productive infection and for latency. In this study, proteomic and phosphoproteomic tools showed the occurrence of changes in Madin-Darby bovine kidney cells at the early stage of the infection by bovine herpesvirus 1 (BoHV-1). Proteins that had already been described in the early stage of infection for other herpesviruses but not for BoHV-1 were found. For example, stathmin phosphorylation at the initial stage of infection is described for the first time. In addition, two proteins that had not been described yet in the early stages of herpesvirus infections in general were ribonuclease/angiogenin inhibitor and Rab GDP dissociation inhibitor beta. The biological processes involved in these cellular responses were repair and replication of DNA, splicing, microtubule dynamics, and inflammatory responses. These results reveal pathways that might be used as targets for designing antiviral molecules against BoHV-1 infection.


Assuntos
Infecções por Herpesviridae/metabolismo , Herpesvirus Bovino 1/patogenicidade , Proteômica/métodos , Proteínas Virais/metabolismo , Animais , Bovinos , Linhagem Celular , Infecções por Herpesviridae/virologia , Herpesvirus Bovino 1/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Espectrometria de Massas , Fosforilação , Mapas de Interação de Proteínas , Estatmina/metabolismo , Replicação Viral
6.
Phytopathology ; 110(1): 164-173, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31532352

RESUMO

Potato virus Y (PVY; Potyviridae) is a continuing challenge for potato production owing to the increasing popularity of strain-specific resistant cultivars. Hypersensitive resistance (HR) is one type of plant defense responses to restrict virus spread. In many potato cultivars, such as cultivar Premier Russet (PR), local necrosis at the site of infection protects against the most common PVYO strain, but the HR often fails to restrain necrotic strains, which spread systemically. Here, we established the role of callose accumulation in the strain-specific resistance responses to PVY infection. We first uncovered that PVY, independent of the strain, is naturally capable of suppressing pathogenesis-related callose formation in a susceptible host. Such activity can be dissociated from viral replication by the transient expression of the viral-encoded helper component proteinase (HCPro) protein, identifying it as the pathogen elicitor. However, unlike the necrotic strain, PVYO and its corresponding HCPro are unable to block callose accumulation in resistant PR potatoes, in which we observed an abundance of callose deposition and the inability of the virus to spread. The substitution of eight amino acid residues within the HCPro C-terminal region that differ between PVYO and PVYN strains and were previously shown to be responsible for eliciting the HR response, are sufficient to restore the ability of HCProO to suppress callose accumulation, despite the resistant host background, in line with a new viral function in pathogenicity.


Assuntos
Cisteína Endopeptidases , Resistência à Doença , Glucanos , Potyvirus , Solanum tuberosum , Proteínas Virais , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Glucanos/metabolismo , Potyvirus/enzimologia , Potyvirus/genética , Potyvirus/fisiologia , Solanum tuberosum/virologia , Especificidade da Espécie , Proteínas Virais/genética , Proteínas Virais/metabolismo , Replicação Viral
7.
Chemistry ; 26(1): 49-88, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31483909

RESUMO

Drugs in the chemical space beyond the rule of 5 (bRo5) can modulate targets with difficult binding sites while retaining cell permeability and oral absorption. Reviewing the syntheses of bRo5 drugs approved since 1990 highlights synthetic chemistry's contribution to drug discovery in this space. Initially, bRo5 drugs were mainly natural products and semi-synthetic derivatives. Later, peptidomimetics and de novo designed compounds, that include up to seven chiral centres and macrocyclic rings became dominant. These drugs are prepared by total synthesis, sometimes by routes of more than 25 steps with stereocentres originating from the chiral pool, or being installed by chiral induction or enzymatic resolution. Interestingly, ring-closing metathesis proved to be the method of choice for macrocyclisation in hepatitis C virus protease inhibitors. We conclude that structural simplification, planning of synthetic routes regarding incorporation of stereocentres and macrocyclisation, as well as incorporation of structural knowledge and consideration of chameleonic properties in design, should facilitate drug discovery in bRo5 space.


Assuntos
Descoberta de Drogas , Preparações Farmacêuticas/síntese química , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Hepacivirus/enzimologia , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/química , Compostos Macrocíclicos/metabolismo , Peptidomiméticos , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Inibidores de Proteases/síntese química , Inibidores de Proteases/química , Inibidores de Proteases/metabolismo , Ribossomos/química , Ribossomos/metabolismo , Proteínas Virais/química , Proteínas Virais/metabolismo
8.
Arch Virol ; 165(2): 355-366, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31845156

RESUMO

Picornaviruses infect a wide range of mammals including livestock such as cattle and swine. As with other picornavirus genera such as Aphthovirus, there is emerging evidence of a significant economic impact of livestock infections caused by members of the genera Enterovirus and Kobuvirus. While the human-infecting enteroviruses and kobuviruses have been intensively studied during the past decades in great detail, research on livestock-infecting viruses has been mostly limited to the genomic characterization of the viral strains identified worldwide. Here, we extend our previous studies of the structure and function of the complexes composed of the non-structural 3A proteins of human-infecting enteroviruses and kobuviruses and the host ACBD3 protein and present a structural and functional characterization of the complexes of the following livestock-infecting picornaviruses: bovine enteroviruses EV-E and EV-F, porcine enterovirus EV-G, and porcine kobuvirus AiV-C. We present a series of crystal structures of these complexes and demonstrate the role of these complexes in facilitation of viral replication.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Infecções por Enterovirus/metabolismo , Enterovirus Bovino/patogenicidade , Enterovirus Suínos/patogenicidade , Kobuvirus/patogenicidade , Proteínas de Membrana/metabolismo , Infecções por Picornaviridae/metabolismo , Animais , Bovinos , Linhagem Celular , Infecções por Enterovirus/veterinária , Infecções por Enterovirus/virologia , Enterovirus Suínos/genética , Células HEK293 , Humanos , Kobuvirus/genética , Infecções por Picornaviridae/veterinária , Infecções por Picornaviridae/virologia , Suínos , Proteínas Virais/genética , Proteínas Virais/metabolismo , Replicação Viral/genética
9.
Int J Cancer ; 146(2): 305-320, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31566705

RESUMO

Cervical cancer (CC) is the fourth most common cause of cancer death in women. The most important risk factor for the development of CC is cervical infection with human papilloma virus (HPV). Inflammation is a protective strategy that is triggered by the host against pathogens such as viral infections that acts rapidly to activate the innate immune response. Inflammation is beneficial if it is brief and well controlled; however, if the inflammation is excessive or it becomes of chronic duration, it can produce detrimental effects. HPV proteins are involved, both directly and indirectly, in the development of chronic inflammation, which is a causal factor in the development of CC. However, other factors may also have a potential role in stimulating chronic inflammation. MicroRNAs (miRNAs) (a class of noncoding RNAs) are strong regulators of gene expression. They have emerged as key players in several biological processes, including inflammatory pathways. Abnormal expression of miRNAs may be linked to the induction of inflammation that occurs in CC. Exosomes are a subset of extracellular vesicles shed by almost all types of cells, which can function as cargo transfer vehicles. Exosomes contain proteins and genetic material (including miRNAs) derived from their parent cells and can potentially affect recipient cells. Exosomes have recently been recognized to be involved in inflammatory processes and can also affect the immune response. In this review, we discuss the role of HPV proteins, miRNAs and exosomes in the inflammation associated with CC.


Assuntos
Exossomos/imunologia , Inflamação/imunologia , MicroRNAs/metabolismo , Infecções por Papillomavirus/imunologia , Neoplasias do Colo do Útero/imunologia , Feminino , Regulação da Expressão Gênica/imunologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Inflamação/patologia , Inflamação/virologia , Papillomaviridae/imunologia , Papillomaviridae/patogenicidade , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/virologia , Fatores de Risco , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/virologia , Proteínas Virais/imunologia , Proteínas Virais/metabolismo
10.
J Enzyme Inhib Med Chem ; 35(1): 145-151, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31724441

RESUMO

There were severe panics caused by Severe Acute Respiratory Syndrome (SARS) and Middle-East Respiratory Syndrome-Coronavirus. Therefore, researches targeting these viruses have been required. Coronaviruses (CoVs) have been rising targets of some flavonoids. The antiviral activity of some flavonoids against CoVs is presumed directly caused by inhibiting 3C-like protease (3CLpro). Here, we applied a flavonoid library to systematically probe inhibitory compounds against SARS-CoV 3CLpro. Herbacetin, rhoifolin and pectolinarin were found to efficiently block the enzymatic activity of SARS-CoV 3CLpro. The interaction of the three flavonoids was confirmed using a tryptophan-based fluorescence method, too. An induced-fit docking analysis indicated that S1, S2 and S3' sites are involved in binding with flavonoids. The comparison with previous studies showed that Triton X-100 played a critical role in objecting false positive or overestimated inhibitory activity of flavonoids. With the systematic analysis, the three flavonoids are suggested to be templates to design functionally improved inhibitors.


Assuntos
Antivirais/farmacologia , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Vírus da SARS/efeitos dos fármacos , Proteínas Virais/antagonistas & inibidores , Antivirais/síntese química , Antivirais/química , Cisteína Endopeptidases/isolamento & purificação , Cisteína Endopeptidases/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Flavonoides/síntese química , Flavonoides/química , Humanos , Estrutura Molecular , Vírus da SARS/enzimologia , Relação Estrutura-Atividade , Proteínas Virais/isolamento & purificação , Proteínas Virais/metabolismo
11.
Gene ; 723: 144134, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31589960

RESUMO

Viral kinases are known to undergo autophosphorylation and also phosphorylate viral and host substrates. Viral kinases have been implicated in various diseases and are also known to acquire host kinases for mimicking cellular functions and exhibit virulence. Although substantial analyses have been reported in the literature on diversity of viral kinases, there is a gap in the understanding of sequence and structural similarity among kinases from different classes of viruses. In this study, we performed a comprehensive analysis of protein kinases encoded in viral genomes. Homology search methods have been used to identify kinases from 104,282 viral genomic datasets. Serine/threonine and tyrosine kinases are identified only in 390 viral genomes. Out of seven viral classes that are based on nature of genetic material, only viruses having double-stranded DNA and single-stranded RNA retroviruses are found to encode kinases. The 716 identified protein kinases are classified into 63 subfamilies based on their sequence similarity within each cluster, and sequence signatures have been identified for each subfamily. 11 clusters are well represented with at least 10 members in each of these clusters. Kinases from dsDNA viruses, Phycodnaviridae which infect green algae and Herpesvirales that infect vertebrates including human, form a major group. From our analysis, it has been observed that the protein kinases in viruses belonging to same taxonomic lineages form discrete clusters and the kinases encoded in alphaherpesvirus form host-specific clusters. A comprehensive sequence and structure-based analysis enabled us to identify the conserved residues or motifs in kinase catalytic domain regions across all viral kinases. Conserved sequence regions that are specific to a particular viral kinase cluster and the kinases that show close similarity to eukaryotic kinases were identified by using sequence and three-dimensional structural regions of eukaryotic kinases as reference. The regions specific to each viral kinase cluster can be used as signatures in the future in classifying uncharacterized viral kinases. We note that kinases from giant viruses Marseilleviridae have close similarity to viral oncogenes in the functional regions and in putative substrate binding regions indicating their possible role in cancer.


Assuntos
Proteínas Quinases/química , Proteínas Quinases/genética , Vírus/classificação , Domínio Catalítico , Biologia Computacional/métodos , Bases de Dados de Proteínas , Variação Genética , Fosforilação , Filogenia , Proteínas Quinases/metabolismo , Homologia de Sequência de Aminoácidos , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo , Fatores de Virulência/química , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Vírus/enzimologia , Vírus/patogenicidade
12.
BMC Infect Dis ; 19(1): 954, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31706275

RESUMO

BACKGROUND: Mumps is a vaccine-preventable disease but outbreaks have been reported in persons vaccinated with two doses of MMR vaccine. The objective was to describe the demographic features, vaccination effectiveness and genetic mumps virus diversity among laboratory-confirmed cases between 2007 and 2011 in Catalonia. METHODS: Cases and outbreaks of mumps notified to the notifiable diseases system of Catalonia between 2007 and 2011 retrospectively registered were included. Public health care centres provided written immunization records to regional public health staff to determine the vaccination history. Saliva and serum specimens were collected from suspected cases for laboratory-confirmation using real-time reverse-transcriptase PCR (rtRT-PCR) or serological testing. Phylogenetic analysis of the complete SH gene (316 nucleotides) and complete coding HN protein (1749 nucleotides) sequences was made. Categorical variables were compared using the Chi-square or Fisher's tests and continuous variables using the Student test. Vaccination effectiveness by number of MMR doses was estimated using the screening method. RESULTS: During the study period, 581 confirmed cases of mumps were notified (incidence rate 1.6 cases/100,000 persons-year), of which 60% were male. Three hundred sixty-four laboratory-confirmed cases were reported, of which 44% were confirmed by rtRT-PCR. Of the 289 laboratory-confirmed cases belonging to vaccination cohorts, 33.5% (97) had received one dose of MMR vaccine and 50% (145) two doses. Based on phylogenetic analyses of 316-nucleotide and 174-nucleotide SH sequences, the viruses belonging to viral genotypes were: genotype G (126), genotype D (23), genotype H (2), genotype F (2), genotype J (1), while one remained uncharacterized. Amino acid differences were detected between circulating strains and the Jeryl Lynn vaccine strains, although the majority of amino acid substitutions were genotype-specific. Fifty-one outbreaks were notified that included 324 confirmed mumps cases. Genotype G was the most frequent genotype detected. The family (35%), secondary schools (25%) and community outbreaks (18%) were the most frequent settings. CONCLUSIONS: Our study shows that genotype G viruses are the most prevalent in Catalonia. Most cases occurred in people who had received two doses of MMR, suggesting inadequate effectiveness of the Jeryl Lynn vaccine strain. The possible factors related are discussed.


Assuntos
Variação Genética , Vacina contra Sarampo-Caxumba-Rubéola/imunologia , Vírus da Caxumba/genética , Vacinação/estatística & dados numéricos , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Genótipo , Humanos , Lactente , Masculino , Caxumba/epidemiologia , Caxumba/imunologia , Caxumba/virologia , Vírus da Caxumba/classificação , Vírus da Caxumba/isolamento & purificação , Filogenia , Estudos Retrospectivos , Saliva/virologia , Espanha/epidemiologia , Proteínas Virais/classificação , Proteínas Virais/genética , Proteínas Virais/metabolismo , Adulto Jovem
13.
Nucleic Acids Res ; 47(16): 8874-8887, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31616952

RESUMO

Localized arrays of proteins cooperatively assemble onto chromosomes to control DNA activity in many contexts. Binding cooperativity is often mediated by specific protein-protein interactions, but cooperativity through DNA structure is becoming increasingly recognized as an additional mechanism. During the site-specific DNA recombination reaction that excises phage λ from the chromosome, the bacterial DNA architectural protein Fis recruits multiple λ-encoded Xis proteins to the attR recombination site. Here, we report X-ray crystal structures of DNA complexes containing Fis + Xis, which show little, if any, contacts between the two proteins. Comparisons with structures of DNA complexes containing only Fis or Xis, together with mutant protein and DNA binding studies, support a mechanism for cooperative protein binding solely by DNA allostery. Fis binding both molds the minor groove to potentiate insertion of the Xis ß-hairpin wing motif and bends the DNA to facilitate Xis-DNA contacts within the major groove. The Fis-structured minor groove shape that is optimized for Xis binding requires a precisely positioned pyrimidine-purine base-pair step, whose location has been shown to modulate minor groove widths in Fis-bound complexes to different DNA targets.


Assuntos
Bacteriófago lambda/genética , Cromossomos Bacterianos/química , DNA Nucleotidiltransferases/química , DNA Bacteriano/química , Proteínas de Escherichia coli/química , Escherichia coli/genética , Fator Proteico para Inversão de Estimulação/química , Proteínas Virais/química , Sítio Alostérico , Bacteriófago lambda/metabolismo , Sequência de Bases , Sítios de Ligação , Cromossomos Bacterianos/metabolismo , Clonagem Molecular , Cristalografia por Raios X , DNA Nucleotidiltransferases/genética , DNA Nucleotidiltransferases/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fator Proteico para Inversão de Estimulação/genética , Fator Proteico para Inversão de Estimulação/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Cinética , Modelos Moleculares , Conformação de Ácido Nucleico , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reparo de DNA por Recombinação , Alinhamento de Sequência , Termodinâmica , Proteínas Virais/genética , Proteínas Virais/metabolismo
14.
Vet Microbiol ; 237: 108381, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31585646

RESUMO

The H5N8 highly pathogenic avian influenza viruses (HPAIVs) isolated in Japan during the 2014-2015 winter differed in their pathogenicity in chickens. In the present study, we examined the possibility that a comparatively less pathogenic strain was first brought into the country by migratory birds, and then acquired enhanced pathogenicity by infecting chicken flocks. We showed that the A/tundra swan/Tottori/C6nk/2014 (H5N8) (Tottori P0) strain required 10 days to kill all chickens via the intranasal route. However, Tottori P1-B, a strain recovered from the brain of a chicken infected with parental Tottori P0, showed enhanced pathogenicity; Tottori P1-B replicated significantly in the lung and liver, and killed all infected birds within 6 days, which was comparable to a chicken farm isolate obtained in the same season, A/environment/Miyazaki/11/2014 (H5N8). Tottori P1-B showed more marked proliferation in MDCK and chicken fibroblast cells, especially during the early phase of infection. Sequence analysis revealed a single mutation, M374 V, in nucleoprotein (NP) of the passaged virus, and this substitution was conserved after a further inoculation study. Position 374 in NP is located in the functional domain interacting with polymerase protein, PB2, indicating that viral polymerase activity was involved in the rapid growth of Tottori P1-B in vitro and in vivo. These results suggest that HPAIV, which originally had comparatively low pathogenicity to chickens, can increase its pathogenicity through the infection from migratory birds to domestic chickens.


Assuntos
Galinhas , Patos , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/virologia , Animais , Linhagem Celular , Embrião de Galinha , Cães , Fibroblastos/virologia , Modelos Moleculares , Conformação Proteica , Proteínas Virais/genética , Proteínas Virais/metabolismo , Virulência
15.
Vet Microbiol ; 237: 108398, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31585653

RESUMO

Feline infectious peritonitis (FIP) is a highly fatal disease caused by a virulent feline coronavirus in domestic and wild cats. We have previously reported the synthesis of potent coronavirus 3C-like protease (3CLpro) inhibitors and the efficacy of a protease inhibitor, GC376, in client-owned cats with FIP. In this study, we studied the effect of the amino acid changes in 3CLpro of feline coronavirus from a feline patient who received antiviral treatment for prolonged duration. We generated recombinant 3CLpro containing the identified amino acid changes (N25S, A252S or K260 N) and determined their susceptibility to protease inhibitors in the fluorescence resonance energy transfer assay. The assay showed that N25S in 3CLpro confers a small change (up to 1.68-fold increase in the 50% inhibitory concentration) in susceptibility to GC376, but other amino acid changes do not affect susceptibility. Modelling of 3CLpro carrying the amino acid changes was conducted to probe the structural basis for these findings. The results of this study may explain the observed absence of clinical resistance to the long-term antiviral treatment in the patients.


Assuntos
Doenças do Gato/virologia , Infecções por Coronaviridae/veterinária , Coronavirus Felino/enzimologia , Peritonite Infecciosa Felina/complicações , Inibidores de Proteases/uso terapêutico , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação , Gatos , Infecções por Coronaviridae/tratamento farmacológico , Infecções por Coronaviridae/virologia , Masculino , Modelos Moleculares , Conformação Proteica , RNA Viral , Alinhamento de Sequência , Proteínas Virais/química , Proteínas Virais/metabolismo
16.
Emerg Microbes Infect ; 8(1): 1465-1478, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31608791

RESUMO

The ANP32A is responsible for mammalian-restricted influenza virus polymerase activity. However, the mechanism of ANP32A modulation of polymerase activity remains poorly understood. Here, we report that chicken ANP32A (chANP32A) -X1 and -X2 stimulated mammalian-restricted PB2 627E polymerase activity in a dose-dependent manner. Distinct effects of ANP32A constructs suggested that the 180VK181 residues within chANP32A-X1 are necessary but not sufficient to stimulate PB2 627E polymerase activity. The PB2 N567D, T598V, A613V or F636L mutations promoted PB2 627E polymerase activity and chANP32A-X1 showed additive effects, providing further support that species-specific regulation of ANP32A might be only relevant with the PB2 E627K mutation. Rescue of cycloheximide-mediated inhibition showed that ANP32A is species-specific for modulation of vRNA but not mRNA and cRNA, demonstrating chANP32A-X1 compensated for defective cRNPs produced by PB2 627E virus in mammalian cells. The promoter mutations of cRNA enhanced the restriction of PB2 627E polymerase in mammalian cells, which could be restored by chANP32A-X1, indicating that ANP32A is likely to regulate the interaction of viral polymerase with RNA promoter. Coimmunoprecipitation showed that ANP32A did not affect the primary cRNPs assembly. We propose a model that chANP32A-X1 regulates PB2 627E polymerase for suitable interaction with cRNA promoter for vRNA replication.


Assuntos
Vírus da Influenza A Subtipo H1N1/enzimologia , Subtipo H7N9 do Vírus da Influenza A/enzimologia , Vírus da Influenza A Subtipo H9N2/enzimologia , Influenza Aviária/metabolismo , Influenza Humana/metabolismo , Doenças das Aves Domésticas/metabolismo , RNA Replicase/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas Virais/metabolismo , Sequência de Aminoácidos , Animais , Galinhas , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/fisiologia , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/fisiologia , Influenza Aviária/genética , Influenza Aviária/virologia , Influenza Humana/genética , Influenza Humana/virologia , Mutação , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Ligação Proteica , RNA Replicase/genética , RNA Viral/genética , RNA Viral/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Alinhamento de Sequência , Especificidade da Espécie , Proteínas Virais/genética , Replicação Viral
17.
Nat Commun ; 10(1): 4460, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575869

RESUMO

Viral infection is an intricate process that requires the concerted action of both viral and host cell components. Entry of viruses into cells is initiated by interactions between viral proteins and their cell surface receptors. Despite recent progress, the molecular mechanisms underlying the multistep reovirus entry process are poorly understood. Using atomic force microscopy, we investigated how the reovirus σ1 attachment protein binds to both α-linked sialic acid (α-SA) and JAM-A cell-surface receptors. We discovered that initial σ1 binding to α-SA favors a strong multivalent anchorage to JAM-A. The enhanced JAM-A binding by virions following α-SA engagement is comparable to JAM-A binding by infectious subvirion particles (ISVPs) in the absence of α-SA. Since ISVPs have an extended σ1 conformer, this finding suggests that α-SA binding triggers a conformational change in σ1. These results provide new insights into the function of viral attachment proteins in the initiation of infection and open new avenues for the use of reoviruses as oncolytic agents.


Assuntos
Polissacarídeos/metabolismo , Polissacarídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Receptores Virais/efeitos dos fármacos , Receptores Virais/metabolismo , Reoviridae/efeitos dos fármacos , Proteínas Virais/metabolismo , Ligação Viral/efeitos dos fármacos , Animais , Células CHO , Moléculas de Adesão Celular , Linhagem Celular , Cricetulus , Interações Hospedeiro-Patógeno , Modelos Moleculares , Ligação Proteica/fisiologia , Receptores de Superfície Celular/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Proteínas Virais/química , Proteínas Virais/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos
18.
J Agric Food Chem ; 67(41): 11380-11387, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31535865

RESUMO

Southern rice black-streaked dwarf virus (SRBSDV) causes disease in crops, which reduces the quality and yield. Several commercial antiviral agents are available to control the SRBSDV induced disease. However, the mechanism of antiviral agents controlling SRBSDV is largely unknown. Identifying targets in SRBSDV is a key step of antiviral agent discovery. Here, we investigated the potential protein target of the antiviral agent dufulin. We cloned and expressed a soluble viroplasmic P6 protein in the prokaryote Escherichia coli and the eukaryote Spodoptera frugiperda 9. The dissociation constants of dufulin with the purified P6 protein from E. coli and S. frugiperda 9 expression systems were 4.49 and 4.95 µM, respectively, indicating a strong binding affinity between dufulin and P6 protein. In vivo, dufulin significantly inhibited the expression of both P6 protein and P6 gene in the SRBSDV-infected rice leaves. This inhibition on P6 protein expression was also observed in transformed Nicotiana benthamiana where the P6 was overexpressed. Our data also showed that dufulin inhibited the duplication of SRBSDV in a dose-dependent manner in infected rice leaves with a half maximum effective concentration of 3.32 mM. It is therefore concluded that dufulin targets the viroplasmic protein P6 to inhibit the virulence of SRBSDV.


Assuntos
Antivirais/farmacologia , Benzotiazóis/farmacologia , Doenças das Plantas/virologia , Reoviridae/efeitos dos fármacos , Proteínas Virais/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Oryza/virologia , Reoviridae/genética , Reoviridae/metabolismo , Proteínas Virais/genética
19.
PLoS Pathog ; 15(9): e1008030, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31518366

RESUMO

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with multiple human malignancies. EBV drives B-cell proliferation, which contributes to the pathogenesis of multiple lymphomas. Yet, knowledge of how EBV subverts host biosynthetic pathways to transform resting lymphocytes into activated lymphoblasts remains incomplete. Using a temporal proteomic dataset of EBV primary human B-cell infection, we identified that cholesterol and fatty acid biosynthetic pathways were amongst the most highly EBV induced. Epstein-Barr nuclear antigen 2 (EBNA2), sterol response element binding protein (SREBP) and MYC each had important roles in cholesterol and fatty acid pathway induction. Unexpectedly, HMG-CoA reductase inhibitor chemical epistasis experiments revealed that mevalonate pathway production of geranylgeranyl pyrophosphate (GGPP), rather than cholesterol, was necessary for EBV-driven B-cell outgrowth, perhaps because EBV upregulated the low-density lipoprotein receptor in newly infected cells for cholesterol uptake. Chemical and CRISPR genetic analyses highlighted downstream GGPP roles in EBV-infected cell small G protein Rab activation. Rab13 was highly EBV-induced in an EBNA3-dependent manner and served as a chaperone critical for latent membrane protein (LMP) 1 and 2A trafficking and target gene activation in newly infected and in lymphoblastoid B-cells. Collectively, these studies identify highlight multiple potential therapeutic targets for prevention of EBV-transformed B-cell growth and survival.


Assuntos
Linfócitos B/virologia , Ácidos Graxos/biossíntese , Herpesvirus Humano 4/patogenicidade , Ácido Mevalônico/metabolismo , Alquil e Aril Transferases/metabolismo , Linfócitos B/patologia , Proliferação de Células , Sobrevivência Celular , Colesterol/biossíntese , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/patologia , Infecções por Vírus Epstein-Barr/virologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/fisiologia , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Redes e Vias Metabólicas , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Proteínas Virais/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo
20.
PLoS Pathog ; 15(9): e1008040, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31527904

RESUMO

To escape CD8+ T-cell immunity, human cytomegalovirus (HCMV) US11 redirects MHC-I for rapid ER-associated proteolytic degradation (ERAD). In humans, classical MHC-I molecules are encoded by the highly polymorphic HLA-A, -B and -C gene loci. While HLA-C resists US11 degradation, the specificity for HLA-A and HLA-B products has not been systematically studied. In this study we analyzed the MHC-I peptide ligands in HCMV-infected cells. A US11-dependent loss of HLA-A ligands was observed, but not of HLA-B. We revealed a general ability of HLA-B to assemble with ß2m and exit from the ER in the presence of US11. Surprisingly, a low-complexity region between the signal peptide sequence and the Ig-like domain of US11, was necessary to form a stable interaction with assembled MHC-I and, moreover, this region was also responsible for changing the pool of HLA-B ligands. Our data suggest a two-pronged strategy by US11 to escape CD8+ T-cell immunity, firstly, by degrading HLA-A molecules, and secondly, by manipulating the HLA-B ligandome.


Assuntos
Citomegalovirus/imunologia , Citomegalovirus/metabolismo , Antígenos HLA-B/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas Virais/metabolismo , Apresentação do Antígeno , Linhagem Celular , Citomegalovirus/genética , Degradação Associada com o Retículo Endoplasmático/imunologia , Antígenos HLA-A/metabolismo , Antígenos HLA-B/química , Células HeLa , Humanos , Evasão da Resposta Imune , Ligantes , Modelos Imunológicos , Modelos Moleculares , Domínios e Motivos de Interação entre Proteínas , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Proteínas Virais/química , Proteínas Virais/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA