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1.
Heliyon ; 9(9): e19613, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37810116

RESUMO

Marburg virus (MARV) is a causative agent of a severe hemorrhagic fever with high fatality rates endemic in central Africa. Current outbreaks of MARV in Equatorial Guinea and Tanzania underline the relevance of MARV as a public health emergency pathogen. In 2021, the first known human MARV case was confirmed in Guinea, West Africa. Since no infectious virus could be isolated from that fatal case in 2021, we generated recombinant (rec) MARV Guinea by reverse genetics in order to study and characterize this new MARV, which occurred in West Africa for the first time, in terms of its growth properties, detection by antibodies, and therapeutic potential compared to known MARV strains. Our results showed a solid viral replication of recMARV Guinea in human, bat, and monkey cell lines in comparison to other known MARV strains. We further demonstrated that replication of recMARV Guinea in cells can be inhibited by the nucleoside analogue remdesivir. Taken together, we could successfully reconstitute de novo the first West African MARV from Guinea showing similar replication kinetics in cells compared to other central African MARV strains. Our reverse genetics approach has proven successful in characterizing emerging viruses, especially when virus isolates are missing and viral genome sequences are incomplete.

2.
Pers Soc Psychol Rev ; 27(1): 52-82, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35676864

RESUMO

Ever since some scientists and popular media put forward the idea that free will is an illusion, the question has risen what would happen if people stopped believing in free will. Psychological research has investigated this question by testing the consequences of experimentally weakening people's free will beliefs. The results of these investigations have been mixed, with successful experiments and unsuccessful replications. This raises two fundamental questions: Can free will beliefs be manipulated, and do such manipulations have downstream consequences? In a meta-analysis including 145 experiments (95 unpublished), we show that exposing individuals to anti-free will manipulations decreases belief in free will and increases belief in determinism. However, we could not find evidence for downstream consequences. Our findings have important theoretical implications for research on free will beliefs and contribute to the discussion of whether reducing people's belief in free will has societal consequences.


Assuntos
Autonomia Pessoal , Humanos
3.
J Cancer Surviv ; 17(6): 1639-1659, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-36459378

RESUMO

PURPOSE: This study aims to examine the magnitude of out of pocket (OOP) payments and income loss, as well as to identify socioeconomic and clinical factors among long-term breast cancer (BC) survivors in Germany. METHODS: We examine data from 2654 long-term BC survivors in Germany that participated in the "CAncEr Survivorship - A multi-Regional population-based study" (CAESAR) and who were at least 5 years post diagnosis. BC-related OOP payments and income loss both within the 12 months prior to the survey were analyzed. Two-part regression models were performed to identify socioeconomic and clinical factors. RESULTS: OOP payments were incurred by 51.9% of survivors with a total mean spending of 566 euros. Income loss was present among 9.6% of survivors and averaged 5463 euros among those reporting such. Socioeconomic and clinical factors associated with higher OOP payments (p ≤ 0.05) included age at time of diagnosis (65-79 years), education (10-11 years), (early) retirement, stage of diagnosis (stage III), time from diagnosis (more than 10 years), comorbidities (at least 1), and the use of rehabilitation services. Regarding income loss, age at time of diagnosis (50-59 years), (early) retirement, stage of diagnosis (stage II), time from diagnosis (5-7 years), comorbidities (at least 1), and receiving chemotherapy treatment were associated with higher losses. CONCLUSIONS: For some survivors in Germany, financial burden can be considerably high despite comprehensive healthcare and support from social security. IMPLICATIONS FOR CANCER SURVIVORS: OOP payments related to domestic help and nursing staff as well as to outpatient care are most frequent.


Assuntos
Neoplasias da Mama , Sobreviventes de Câncer , Humanos , Idoso , Pessoa de Meia-Idade , Feminino , Gastos em Saúde , Neoplasias da Mama/terapia , Renda , Inquéritos e Questionários
4.
Ann Diagn Pathol ; 54: 151793, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34425503

RESUMO

Thyroglobulin is a secreted 660 kDa glycoprotein produced by thyroid follicular cells used in diagnostic pathology to secure or exclude a thyroidal origin of metastases of unknown primary tumors. This study was performed to estimate specificity of thyroglobulin immunohistochemistry. 9974 tumor samples from 109 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Thyroglobulin was strongly expressed in all normal thyroid samples but not in any other normal tissues. Thyroglobulin immunostaining was detected in 99.1% of 106 thyroid adenomas, 98.1% of 364 papillary, 95.2% of 147 follicular, and 7.5% of 40 anaplastic thyroid cancers. Twelve of 15 thyroid samples that were thyroglobulin negative on TMAs showed at least a weak focal thyroglobulin positivity in corresponding large sections, suggesting higher sensitivity of large section analysis. Thyroglobulin positivity in one diffuse large B-cell lymphoma of the thyroid, one chondrosarcoma metastasis to the thyroid, and 42.4% of 92 medullary thyroid cancers was considered to be caused by diffusion of thyroidal colloid from destroyed or even intact adjacent follicles. Thyroglobulin positivity was, however, not seen in 6403 extrathyroidal tumors from 104 different tumor types and subtypes. Our data demonstrate a complete specificity of positive thyroglobulin immunostaining for thyroid origin in tumor tissues obtained from extrathyroidal locations. However, for all tumors located within the thyroid, false positivity can occur as a result of tissue contamination by thyroglobulin rich thyroid colloid from adjacent normal tissue.


Assuntos
Carcinoma Neuroendócrino/metabolismo , Imuno-Histoquímica , Tireoglobulina/metabolismo , Neoplasias da Glândula Tireoide/patologia , Carcinoma Neuroendócrino/patologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Imuno-Histoquímica/métodos , Tireoglobulina/análise , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/metabolismo
6.
Int J Mol Sci ; 20(21)2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31731509

RESUMO

During characterization of a cDNA library from the Hodgkin lymphoma (HL) cell line L-1236, we discovered a new transcript derived from chromosome 1 at the long intergenic non-protein coding RNA 1768 (LINC01768)/colony stimulating factor 1 (CSF1) region. The first exon of this transcript from Hodgkin lymphoma cells (THOLE) starts in the predicted exon 4 of LINC01768 and is part of an endogenous retrovirus (ERV) from the HUERS-P1/LTR8 family. High expression of THOLE was only detectable in HL cell line L-1236. The expression of THOLE in L-1236 cell is another example for ERV/LTR-associated gene expression in HL cells. At the genome level, the HUERS-P1/LTR8 region including THOLE is only present in Hominoidea. The influence of ERV/LTRs on gene expression might explain the characteristic phenotype of human HL.


Assuntos
Retrovirus Endógenos , Regulação Neoplásica da Expressão Gênica , Regulação Viral da Expressão Gênica , Doença de Hodgkin , Retrovirus Endógenos/genética , Retrovirus Endógenos/metabolismo , Doença de Hodgkin/genética , Doença de Hodgkin/metabolismo , Doença de Hodgkin/virologia , Humanos , Células Jurkat
7.
FEMS Microbiol Ecol ; 94(8)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29701793

RESUMO

Conservation tillage and organic farming are strategies used worldwide to preserve the stability and fertility of soils. While positive effects on soil structure have been extensively reported, the effects on specific root- and soil-associated microorganisms are less known. The aim of this study was to investigate how conservation tillage and organic farming influence the frequency and activity of plant-beneficial pseudomonads. Amplicon sequencing using the 16S rRNA gene revealed that Pseudomonas is among the most abundant bacterial taxa in the root microbiome of field-grown wheat, independent of agronomical practices. However, pseudomonads carrying genes required for the biosynthesis of specific antimicrobial compounds were enriched in samples from conventionally farmed plots without tillage. In contrast, disease resistance tests indicated that soil from conventional no tillage plots is less resistant to the soilborne pathogen Pythium ultimum compared to soil from organic reduced tillage plots, which exhibited the highest resistance of all compared cropping systems. Reporter strain-based gene expression assays did not reveal any differences in Pseudomonas antimicrobial gene expression between soils from different cropping systems. Our results suggest that plant-beneficial pseudomonads can be favoured by certain soil cropping systems, but soil resistance against plant diseases is likely determined by a multitude of biotic factors in addition to Pseudomonas.


Assuntos
Antibiose/fisiologia , Antiparasitários/metabolismo , Resistência à Doença/fisiologia , Agricultura Orgânica/métodos , Doenças das Plantas/prevenção & controle , Doenças das Plantas/parasitologia , Raízes de Plantas/microbiologia , Pseudomonas/metabolismo , Pythium/efeitos dos fármacos , Triticum/parasitologia , Fazendas , Microbiota , Pseudomonas/genética , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Solo/química , Microbiologia do Solo , Triticum/microbiologia
8.
Front Plant Sci ; 8: 427, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28424714

RESUMO

Strains of Pseudomonas that produce antimicrobial metabolites and control soilborne plant diseases have often been isolated from soils defined as disease-suppressive, i.e., soils, in which specific plant pathogens are present, but plants show no or reduced disease symptoms. Moreover, it is assumed that pseudomonads producing antimicrobial compounds such as 2,4-diacetylphloroglucinol (DAPG) or phenazines (PHZ) contribute to the specific disease resistance of suppressive soils. However, pseudomonads producing antimicrobial metabolites are also present in soils that are conducive to disease. Currently, it is still unknown whether and to which extent the abundance of antimicrobials-producing pseudomonads is related to the general disease resistance of common agricultural soils. Moreover, virtually nothing is known about the conditions under which pseudomonads express antimicrobial genes in agricultural field soils. We present here results of the first side-by-side comparison of 10 representative Swiss agricultural soils with a cereal-oriented cropping history for (i) the resistance against two soilborne pathogens, (ii) the abundance of Pseudomonas bacteria harboring genes involved in the biosynthesis of the antimicrobials DAPG, PHZ, and pyrrolnitrin on roots of wheat, and (iii) the ability to support the expression of these genes on the roots. Our study revealed that the level of soil disease resistance strongly depends on the type of pathogen, e.g., soils that are highly resistant to Gaeumannomyces tritici often are highly susceptible to Pythium ultimum and vice versa. There was no significant correlation between the disease resistance of the soils, the abundance of Pseudomonas bacteria carrying DAPG, PHZ, and pyrrolnitrin biosynthetic genes, and the ability of the soils to support the expression of the antimicrobial genes. Correlation analyses indicated that certain soil factors such as silt, clay, and some macro- and micronutrients influence both the abundance and the expression of the antimicrobial genes. Taken together, the results of this study suggests that pseudomonads producing DAPG, PHZ, or pyrrolnitrin are present and abundant in Swiss agricultural soils and that the soils support the expression of the respective biosynthetic genes in these bacteria to various degrees. The precise role that these pseudomonads play in the general disease resistance of the investigated agricultural soils remains elusive.

9.
Sci Rep ; 6: 39635, 2016 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-28004762

RESUMO

To prevent bacterial contamination on textiles and the associated undesired effects different biocidal coatings have been investigated and applied. However, due to health and environmental concerns anti-adhesive coatings preventing the binding of bacteria would be favored. To develop such anti-adhesive coatings simple assays for reliable and fast screening are beneficial. Here an easy-to-handle, robust and rapid assay to assess bacteria on textiles utilizing a tetrazolium salt was reported. The assay allowed direct eye visualization of the color change of the textiles containing bacteria, facilitating fast screening. Quantification of the adhered bacteria could be done by generating standard curves which correlate the staining intensity to cell numbers. An additional advantage of the described assay is that with the same detection method anti-adhesive and biocidal effects can be investigated. The method was applied to different coatings, using Pseudomonas aeruginosa and Staphylococcus aureus as model organisms. The detection limit was found to be between 2.5 * 106 and 9.4 * 108 for P. aeruginosa and between 1 * 106 and 3.3 * 108 for S. aureus. The anti-adhesive coating PLUMA was demonstrated to reduce bacterial adhesion without killing them, whereas the biocidal coating TH22-27 caused a clear reduction in the number of viable cells.


Assuntos
Aderência Bacteriana , Pseudomonas aeruginosa/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Têxteis/microbiologia , Limite de Detecção , Microscopia , Microscopia de Fluorescência , Reprodutibilidade dos Testes , Espectrofotometria , Sais de Tetrazólio/química
10.
Antimicrob Agents Chemother ; 60(6): 3647-52, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27044552

RESUMO

Efficient removal of biofilms from medical devices is a big challenge in health care to avoid hospital-acquired infections, especially from delicate devices like flexible endoscopes, which cannot be reprocessed using harsh chemicals or high temperatures. Therefore, milder solutions such as enzymatic cleaners have to be used, which need to be carefully developed to ensure efficacious performance. In vitro biofilm in a 96-well-plate system was used to select and optimize the formulation of novel enzymatic cleaners. Removal of the biofilm was quantified by crystal violet staining, while the disinfecting properties were evaluated by a BacTiter-Glo assay. The biofilm removal efficacy of the selected cleaner was further tested by using European standard (EN) for endoscope cleaning EN ISO 15883, and removal of artificial blood soil was investigated by treating TOSI (Test Object Surgical Instrument) cleaning indicators. Using the process described here, a novel enzymatic endoscope cleaner was developed, which removed 95% of Staphylococcus aureus and 90% of Pseudomonas aeruginosa biofilms in the 96-well plate system. With a >99% reduction of CFU and a >90% reduction of extracellular polymeric substances, this cleaner enabled subsequent complete disinfection and fulfilled acceptance criteria of EN ISO 15883. Furthermore, it efficiently removed blood soil and significantly outperformed comparable commercial products. The cleaning performance was stable even after storage of the cleaner for 6 months. It was demonstrated that incorporation of appropriate enzymes into the cleaner enhanced performance significantly.


Assuntos
Biofilmes/efeitos dos fármacos , Desoxirribonucleases/farmacologia , Desinfetantes/farmacologia , Lipase/farmacologia , Peptídeo Hidrolases/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Infecção Hospitalar/prevenção & controle , Desoxirribonucleases/química , Detergentes/química , Detergentes/farmacologia , Desinfetantes/química , Desinfecção , Endoscópios/microbiologia , Contaminação de Equipamentos , Humanos , Lipase/química , Peptídeo Hidrolases/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Pseudomonas aeruginosa/fisiologia , Staphylococcus aureus/fisiologia
11.
Appl Microbiol Biotechnol ; 100(9): 4135-45, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26923144

RESUMO

Various methods have been reported to quantify total biofilm or different components of biofilm; however, these methods are often confusedly used, leading to discrepancies and misleading results. In this study, different methods for quantification of biofilm, including those for total biomass, total amount of bacterial cells, viable cell number, and amount of extracellular polymeric substances, were systematically compared in microtiter plates. To evaluate which method is suitable for assessment of biofilm removal and for bacterial killing, biofilm samples were treated with various cleaners possessing removing and/or killing capacities. It was found that most of the methods tested in this study in general exhibited high reproducibility and repeatability. Crystal Violet staining was a simple but reliable method for total biomass quantification. Total bacteria cell numbers could be reliably quantified by the fluorescent DNA-binding dye Acridine Orange. Viable cells could be quantified by either an ATP-based assay or a proliferation assay. Both of these viability methods showed a broad detection range and led to precise measurement. For quantification of proteins in the biofilm, staining with fluorescein isothiocyanate was most suitable. Furthermore, it was revealed that a combination of different methods is required to determine if a cleaner kills or removes biofilm.


Assuntos
Bactérias/efeitos dos fármacos , Técnicas Bacteriológicas/métodos , Biofilmes/efeitos dos fármacos , Desinfecção/métodos , Carga Bacteriana , Biomassa , Viabilidade Microbiana/efeitos dos fármacos , Reprodutibilidade dos Testes
12.
Anim Reprod Sci ; 146(1-2): 34-41, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24598214

RESUMO

In the equine species, sex determination of the conceptus is of growing interest for the breeding industry. In horses, the sex ratio of the offspring depends on changes in body condition of the mother at conception and under natural conditions may thus markedly deviate from an expected 1:1 ratio. Insemination with sex-sorted spermatozoa allows a pronounced shift of the sex ratio but at present pregnancy rates are low and vary considerably under field conditions. In equine embryo transfer programmes, sex determination in embryos before transfer via genetic methods is a promising approach with high reliability. In ongoing pregnancies, fetal sex can be determined in utero by transrectal or transabdominal ultrasound between days 57 and 220 after ovulation, but experience is required to achieve satisfying accuracy. Recently, genetic sexing via identification of circulating cell-free fetal DNA in the maternal circulation has been successfully performed in the last three months of pregnancy. Development of this technique may also allow fetal sex determination at earlier stages of pregnancy. Further research is required to allow for techniques that enable sex determination in equine embryos as well as in ongoing pregnancies under field conditions.


Assuntos
Cavalos/fisiologia , Análise para Determinação do Sexo/veterinária , Processos de Determinação Sexual , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Animais , Transferência Embrionária/veterinária , Feminino , Genitália/diagnóstico por imagem , Masculino , Análise para Determinação do Sexo/métodos , Processos de Determinação Sexual/fisiologia , Pré-Seleção do Sexo/veterinária , Razão de Masculinidade , Ultrassonografia
13.
Vaccine ; 27(45): 6312-6, 2009 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-19840666

RESUMO

Although it is known for decades that influenza viruses replicate and transcribe their genome in the nucleus of the host cell, there is little knowledge about the cellular and viral factors mediating the nuclear transport of viral mRNA transcripts to the cytoplasm. Efficient export of mature cellular mRNA is coupled to their synthesis by the RNA polymerase II and subsequent processing events such as splicing. This linkage necessitated influenza viruses to evolve a strategy to integrate their unspliced mRNAs generated by the viral polymerase into a cellular mRNA export pathway. Recent findings suggest that the major cellular mRNA export receptor Tap/NXF1 promotes the influenza virus mRNA export. Here, we review functions of the NS1 proteins of influenza A and B viruses and discuss the emerging evidence supporting a role of these viral factors in the export of viral mRNAs.


Assuntos
Vírus da Influenza A/genética , Vírus da Influenza B/genética , Transporte de RNA , Proteínas não Estruturais Virais/metabolismo , Transporte Ativo do Núcleo Celular , Regulação Viral da Expressão Gênica , Vírus da Influenza A/metabolismo , Vírus da Influenza A/fisiologia , Vírus da Influenza B/metabolismo , Vírus da Influenza B/fisiologia , RNA Mensageiro/metabolismo , RNA Viral/metabolismo , Proteínas não Estruturais Virais/genética , Replicação Viral
14.
PLoS Pathog ; 5(6): e1000473, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19521506

RESUMO

Activation of the latent kinase PKR is a potent innate defense reaction of vertebrate cells towards viral infections, which is triggered by recognition of viral double-stranded (ds) RNA and results in a translational shutdown. A major gap in our understanding of PKR's antiviral properties concerns the nature of the kinase activating molecules expressed by influenza and other viruses with a negative strand RNA genome, as these pathogens produce little or no detectable amounts of dsRNA. Here we systematically investigated PKR activation by influenza B virus and its impact on viral pathogenicity. Biochemical analysis revealed that PKR is activated by viral ribonucleoprotein (vRNP) complexes known to contain single-stranded RNA with a 5'-triphosphate group. Cell biological examination of recombinant viruses showed that the nucleo-cytoplasmic transport of vRNP late in infection is a strong trigger for PKR activation. In addition, our analysis provides a mechanistic explanation for the previously observed suppression of PKR activation by the influenza B virus NS1 protein, which we show here to rely on complex formation between PKR and NS1's dsRNA binding domain. The high significance of this interaction for pathogenicity was revealed by the finding that attenuated influenza viruses expressing dsRNA binding-deficient NS1 proteins were rescued for high replication and virulence in PKR-deficient cells and mice, respectively. Collectively, our study provides new insights into an important antiviral defense mechanism of vertebrates and leads us to suggest a new model of PKR activation by cytosolic vRNP complexes, a model that may also be applicable to other negative strand RNA viruses.


Assuntos
Vírus da Influenza B/fisiologia , Vírus da Influenza B/patogenicidade , Ribonucleoproteínas/metabolismo , Proteínas Virais/metabolismo , eIF-2 Quinase/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , Citoplasma/metabolismo , Ativação Enzimática , Feminino , Humanos , Vírus da Influenza B/genética , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Modelos Biológicos , Fosforilação , RNA de Cadeia Dupla/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral
15.
J Virol ; 83(2): 701-11, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18987144

RESUMO

Many proteins that function in the transcription, maturation, and export of metazoan mRNAs are concentrated in nuclear speckle domains, indicating that the compartment is important for gene expression. Here, we show that the NS1 protein of influenza B virus (B/NS1) accumulates in nuclear speckles and causes rounding and morphological changes of the domains, indicating a disturbance in their normal functions. This property was located within the N-terminal 90 amino acids of the B/NS1 protein and was shown to be independent of any other viral gene product. Within this protein domain, we identified a monopartite importin alpha binding nuclear localization signal. Reverse-genetic analysis of this motif indicated that nuclear import and speckle association of the B/NS1 protein are required for the full replication capacity of the virus. In the late phase of virus infection, the B/NS1 protein relocated to the cytoplasm, which occurred in a CRM1-independent manner. The interaction of the B/NS1 protein with nuclear speckles may reflect a recruitment function to promote viral-gene expression. To our knowledge, this is the first functional description of a speckle-associated protein that is encoded by a negative-strand RNA virus.


Assuntos
Vírus da Influenza B/fisiologia , Proteínas não Estruturais Virais/metabolismo , Replicação Viral , Animais , Linhagem Celular , Núcleo Celular/química , Citoplasma/química , Humanos , Sinais de Localização Nuclear , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas , Spodoptera , Proteínas não Estruturais Virais/genética
16.
J Virol ; 83(2): 1147-51, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19004958

RESUMO

ISG15 functions as a critical antiviral molecule against influenza virus, with infection inducing both the conjugation of ISG15 to target proteins and production of free ISG15. Here, we report that mice lacking the ISG15 E1 enzyme UbE1L fail to form ISG15 conjugates. Both UbE1L(-/-) and ISG15(-/-) mice display increased susceptibility to influenza B virus infection, including non-mouse-adapted strains. Finally, we demonstrate that ISG15 controls influenza B virus infection through its action within radioresistant stromal cells and not bone marrow-derived cells. Thus, the conjugation of ISG15 to target proteins within stromal cells is critical to its activity against influenza virus.


Assuntos
Citocinas/deficiência , Predisposição Genética para Doença , Vírus da Influenza B/imunologia , Infecções por Orthomyxoviridae/imunologia , Enzimas Ativadoras de Ubiquitina/deficiência , Animais , Pulmão/virologia , Camundongos , Análise de Sobrevida , Ubiquitinas/deficiência
17.
J Virol ; 80(23): 11667-77, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16987984

RESUMO

Expression of alpha/beta interferon (IFN-alpha/beta) in virus-infected vertebrate cells is a key event in the establishment of a sustained antiviral response, which is triggered by double-stranded RNA (dsRNA) produced during viral replication. These antiviral cytokines initiate the expression of cellular proteins with activities that limit the replication and spread of the invading viruses. Within this response, the dsRNA-dependent protein kinase R (PKR) that is expressed at constitutive levels and upregulated by IFN-alpha/beta acts as an important antiviral effector that can block the cellular translational machinery. We previously demonstrated that efficient replication of influenza B virus depends on the viral dsRNA-binding NS1 protein that inhibits the transcriptional activation of IFN-alpha/beta genes. Here we tested the postulate that the viral NS1 protein counteracts antiviral responses through sequestering intracellular dsRNA by analyzing a collection of recombinant influenza B viruses. As expected, viruses expressing dsRNA-binding-defective NS1 proteins were strongly attenuated for replication in IFN-competent hosts. Interestingly, these virus mutants failed to prevent activation of PKR but could effectively limit IFN induction. Conversely, a mutant virus expressing the N-terminal dsRNA-binding domain of NS1 prevented PKR activation, but not IFN induction, suggesting an important role for the NS1 C-terminal part in silencing the activation route of IFN-alpha/beta genes. Thus, our findings indicate an unexpected mechanistic dichotomy of the influenza B virus NS1 protein in the suppression of antiviral responses, which involves at least one activity that is largely separable from dsRNA binding.


Assuntos
Vírus da Influenza B/química , Interferon-alfa/metabolismo , Interferon beta/metabolismo , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas não Estruturais Virais/farmacologia , eIF-2 Quinase/antagonistas & inibidores , Linhagem Celular , Regulação Viral da Expressão Gênica , Interferon-alfa/genética , Interferon beta/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas não Estruturais Virais/metabolismo
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