RESUMO
In this paper, we report results on the electronic structure and transport properties of molecular junctions fabricated via conducting probe atomic force microscopy (CP-AFM) using self-assembled monolayers (SAMs) of n-alkyl chains anchored with acetylene groups (CnA; n = 8, 9, 10, and 12) on Ag, Au, and Pt electrodes. We found that the current-voltage (I-V) characteristics of CnA CP-AFM junctions can be very accurately reproduced by the same off-resonant single-level model (orSLM) successfully utilized previously for many other junctions. We demonstrate that important insight into the energy-level alignment can be gained from experimental data of transport (processed via the orSLM) and ultraviolet photoelectron spectroscopy combined with ab initio quantum chemical information based on the many-body outer valence Green's function method. Measured conductance GAg < GAu < GPt is found to follow the same ordering as the metal work function ΦAu < ΦAu < ΦPt, a fact that points toward a transport mediated by an occupied molecular orbital (MO). Still, careful data analysis surprisingly revealed that transport is not dominated by the ubiquitous HOMO but rather by the HOMO-1. This is an important difference from other molecular tunnel junctions with p-type HOMO-mediated conduction investigated in the past, including the alkyl thiols (CnT) to which we refer in view of some similarities. Furthermore, unlike in CnT and other junctions anchored with thiol groups investigated in the past, the AFM tip causes in CnA an additional MO shift, whose independence of size (n) rules out significant image charge effects. Along with the prevalence of the HOMO-1 over the HOMO, the impact of the "second" (tip) electrode on the energy level alignment is another important finding that makes the CnA and CnT junctions different. What ultimately makes CnA unique at the microscopic level is a salient difference never reported previously, namely, that CnA's alkyne functional group gives rise to two energetically close (HOMO and HOMO-1) orbitals. This distinguishes the present CnA from the CnT, whose HOMO stemming from its thiol group is well separated energetically from the other MOs.
RESUMO
Acute hepatopancreatic necrosis disease (AHPND) is a highly contagious and lethal disease of shrimp caused by Vibrio strains carrying the virulence plasmid (pAHPND) containing the pirAB virulence genes. Through analysis of plasmid sequence similarity, clustering, and phylogeny, a horizontal transfer element similar to IS91 was discovered within the pAHPND plasmid. Additionally, two distinct clades of plasmids related to pAHPND (designated as pAHPND-r1 and pAHPND-r2) were identified, which may serve as potential parental plasmids for pAHPND. The available evidence, including the difference in G+C content between the plasmid and its host, codon usage preference, and plasmid recombination event prediction, suggests that the formation of the pAHPND plasmid in the Vibrio owensii strain was likely due to the synergistic effect of the recombinase RecA and the associated proteins RecBCD on the pAHPND-r1 and pAHPND-r2, resulting in the recombination and formation of the precursor plasmid for pAHPND (pre-pAHPND). The emergence of pAHPND was found to be a result of successive insertions of the horizontal transfer elements of pirAB-Tn903 and IS91-like segment, which led to the deletion of one third of the pre-pAHPND. This plasmid was then able to spread horizontally to other Vibrio strains, contributing to the epidemics of AHPND. These findings shed light on previously unknown mechanisms involved in the emergence of pAHPND and improve our understanding of the disease's spread.
RESUMO
RNA viruses in marine environments have long been recognized as major players in the virosphere. In this study, the complete genome sequence of an RNA virus from Yangshan Harbor, named marine RNA virus Yangshan-LWW (YS-LWW), was obtained based on metavirome assembly. The genome of YS-LWW is 8839 nt in length and contains two open reading frames (ORFs). Both RdRP- and whole-genome-based phylogenetic analysis showed that YS-LWW, together with 45 viral isolates with sequences in public datasets, represents a new species in the genus Locarnavirus of the family Marnaviridae. PCR and public dataset mining indicate that YS-LWW and YS-LWW-like viruses have been widely detected in coastal and freshwater environments, suggesting that they might play a significant role in aquatic ecosystems.
Assuntos
Ecossistema , Vírus de RNA , Filogenia , Vírus de RNA/genética , Fases de Leitura Aberta , Reação em Cadeia da PolimeraseRESUMO
The intron-based stabilization approach is a very useful strategy for construction of stable flavivirus infectious clones. SA14-14-2 is a highly attenuated Japanese encephalitis (JE) live vaccine strain that has been widely used in China since 1989. To develop safe and effective recombinant vaccines with SA14-14-2 as a backbone vector, we constructed the DNA-based infectious clone pCMW-JEV of SA14-14-2 using the intron-based stabilization approach and acquired the rescued virus rDJEV, which retained the biological properties of the parental virus. Unexpectedly, a rescued virus strain with altered virulence, designated rHV-DJEV, was accidentally acquired in one of the transfection experiments. rHV-DJEV showed up to 105-fold increased neurovirulence compared with the SA14-14-2 parental strain. Genome sequencing showed that the inserted introns were still present in the genome of rHV-DJEV. Therefore, we think that the intron-based stabilization approach should be used with caution in vaccine development and direct iDNA immunization.
Assuntos
Vírus da Encefalite Japonesa (Espécie) , Vacinas contra Encefalite Japonesa , Humanos , Sequência de Bases , Vírus da Encefalite Japonesa (Espécie)/genética , Encefalite Japonesa/prevenção & controle , Genoma Viral , Íntrons , Vacinas contra Encefalite Japonesa/genética , Vacinas Atenuadas/genéticaRESUMO
3D-QSAR models were established by collecting 46 multivariate-substituted 4-oxyquinazoline HDAC6 inhibitors. The relationship of molecular structure and inhibitory activity was studied by comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA). The results showed the models established by CoMFA (q2 = 0.590, r2 = 0.965) and CoMSIA (q2 = 0.594, r2 = 0.931) had good prediction ability. At the same time, 3D-QSAR models met the internal verification, external verification and AD test. Ten new compounds were designed based on CoMFA and CoMSIA contour maps and their pharmacokinetic/toxic properties (ADME/T) were evaluated. It was found that most compounds have well safety profile and pharmacokinetic property. Then, we explored the interaction between HDAC6 and compounds by molecular docking. The results showed that the binding mode of the new compounds with HDAC6 was the same as the template compound 46, and the hydrogen bond and hydrophobic bond played a vital role in the binding process. Molecular dynamics simulation results showed that residues Ser531, His574 and Tyr745 played key roles in the binding process. All newly designed compounds had lower energy gap and binding energy than compound 46 according to DFT analysis and free energy analysis. This study provided a theoretical reference for designing compounds of higher activity and a new idea for the development of novel HDAC6 inhibitors.
Assuntos
Simulação de Dinâmica Molecular , Relação Quantitativa Estrutura-Atividade , Simulação de Acoplamento Molecular , Estrutura MolecularRESUMO
Erlotinib is a first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Overcoming erlotinib resistance is crucial to improve the survival of advanced non-small cell lung cancer (NSCLC) patients with sensitive EGFR mutations. It is also an important clinical problem that urgently needs a solution. In this study, we explored strategies to overcome erlotinib resistance from the perspective of energy metabolism. SIRT6 is a histone deacetylase. Here, we found that high expression of SIRT6 is associated with poor prognosis of lung adenocarcinoma, especially in EGFR-mutated NSCLC patients. The next cell experiment found that SIRT6 expression increased in erlotinib-resistant cells, and SIRT6 expression was negatively correlated with the sensitivity of NSCLC to erlotinib. Inhibition of SIRT6 promoted erlotinib-induced apoptosis in erlotinib-resistant cells, and glycolysis in drug-resistant cells was also inhibited. Functional studies have shown that SIRT6 increases glycolysis through the HIF-1α/HK2 signaling axis in drug-resistant cells and inhibits the sensitivity of NSCLC cells to erlotinib. In addition, the HIF-1α blocker PX478-2HCL attenuated the glycolysis and erlotinib resistance induced by SIRT6. More importantly, we confirmed the antitumor effect of SIRT6 inhibition combined with erlotinib in NSCLC-bearing mice. Our findings indicate that the cancer metabolic pathway regulated by SIRT6 may be a new target for attenuating NSCLC erlotinib resistance and has potential as a biomarker or therapeutic target to improve outcomes in NSCLC patients.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Sirtuínas , Animais , Camundongos , Apoptose , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/genética , Receptores ErbB/metabolismo , Cloridrato de Erlotinib/farmacologia , Cloridrato de Erlotinib/uso terapêutico , Glicólise/genética , Histona Desacetilases/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação , Inibidores de Proteínas Quinases/farmacologia , Sirtuínas/genética , Sirtuínas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , HumanosRESUMO
We have obtained an attenuated rabies virus CTN181-3. In this paper, we make a comprehensive studies on CTN181-3. CTN181-3 showed no pathogenicity by i. c. or o. i. inoculation in 3-week-old mice, lower pathogenic in 2-week-old mice, and no virulence by o. i. inoculation in 8-week-old golden hamsters. CTN181-3 showed high immunogenicity, which produced high level neutralizing antibodies, 100% sero-conversation and >5.0 IU/ml GMT by one dose i. m. or o. i. vaccination in mice and golden hamsters. Cellular immune response by one dose i. m. or o. i. inoculation was detected. Especially in PEP, reduced dose of vaccination resulted in 50% (one dose) and 100% (2 doses) protections in golden hamsters. Molecular basis of the attenuation indicated that eight substitutions compared to its parental virus strain CTN-1, among them the two substitutions at the G276 (LeuâVal) and L1496 (MetâTrp) were the critical attenuated site. The phenotypic and genotypic characteristics of CTN181-3 were highly stable, no reversion was occurred when the virus was multiple passaged in suckling mice brains, guinea pig submandibular glands or BSR/Vero cell cultures. The gene homology compared to the Chinese rabies isolates showed much higher than rabies vaccine strains used in China, suggesting CTN181-3 is a promising and suitable oral rabies vaccine candidate strain.
Assuntos
Vacina Antirrábica , Vírus da Raiva , Raiva , Animais , Anticorpos Antivirais , Chlorocebus aethiops , Cricetinae , Cobaias , Mesocricetus , Camundongos , Raiva/prevenção & controle , Vírus da Raiva/genética , Células VeroRESUMO
A bacterial strain ODT-83 is isolated from oysters, which is capable of adsorbing norovirus (NoV) via histo-blood group antigen-like (HBGA-like) substances. To better understand its genetic background associated with the production of HBGA-like substances, the genome of the ODT-83 was completely sequenced and analyzed. The ODT-83 only contains one circular chromosome, with a length of 5,384,159 bp. Both the 16S rRNA gene phylogeny and the average nucleotide identity (ANI) analyses confirm that the ODT-83 is a new Pseudomonas oleovorans strain. The whole genome encodes a total of 5037 predicted open reading frames (ORFs), 66 tRNA genes and 12 rRNA genes. Two gene clusters are detected on the genome, which are involved in the synthesis of polysaccharides of alginate and Pel, respectively. These results lay the foundation for further research on the interaction between the P. oleovorans strain ODT-83 and NoV.
Assuntos
Genoma Bacteriano , Ostreidae , Pseudomonas oleovorans , Animais , Técnicas de Tipagem Bacteriana , Ácidos Graxos/análise , Genoma Bacteriano/genética , Ostreidae/microbiologia , Filogenia , Pseudomonas/genética , Pseudomonas oleovorans/classificação , Pseudomonas oleovorans/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
A novel F-specific RNA bacteriophage (FRNAPH) YM1, affiliating to genogroup I (GI) of Levivirus, is isolated for the first time from human stool samples using double-layer agar plates with the Escherichia coli ATCC700891 as the host. The complete genomic sequence of YM1 is 3551 nt in length, obtained through next-generation sequencing, and contains four genes encoding for maturation protein, coat protein, lysis protein, and RNA-dependent RNA polymerase (RdRp). The genomic sequence of YM1 shares the highest similarity of 95.3% with that of a GI FRNAPH DL16 isolated from surface water of Great Bay. The YM1 possesses a non-enveloped, icosahedral virion of 23 ± 0.45 nm in diameter. One-step growth curve analysis shows that the burst time of YM1 is 30 min post-infection (p.i.) with the average burst size of 264 PFU/cell. The YM1 lyses only E. coli strains tested, revealing high host specificity. This newly discovered phage may serve as a candidate for viral indicator to monitor human enteric virus, especially norovirus, contamination in the environments.
Assuntos
Bacteriófagos , Monitoramento Ambiental , Fezes , Fagos RNA , Bacteriófagos/genética , Monitoramento Ambiental/métodos , Escherichia coli/virologia , Fezes/virologia , Genoma Viral/genética , Especificidade de Hospedeiro , Humanos , Norovirus/genética , Fagos RNA/genética , Fagos RNA/isolamento & purificaçãoRESUMO
Although significant progress has been made in understanding epigenetic regulation of in vitro adipogenesis, the physiological functions of epigenetic regulators in metabolism and their roles in obesity remain largely elusive. Here, we report that KDM4B (lysine demethylase 4B) in adipose tissues plays a critical role in energy balance, oxidation, lipolysis, and thermogenesis. Loss of KDM4B in mice resulted in obesity associated with reduced energy expenditure and impaired adaptive thermogenesis. Obesity in KDM4B-deficient mice was accompanied by hyperlipidemia, insulin resistance, and pathological changes in the liver and pancreas. Adipocyte-specific deletion of Kdm4b revealed that the adipose tissues were the main sites for KDM4B antiobesity effects. KDM4B directly controlled the expression of multiple metabolic genes, including Ppargc1a and Ppara Collectively, our studies identify KDM4B as an essential epigenetic factor for the regulation of metabolic health and maintaining normal body weight in mice. KDM4B may provide a therapeutic target for treatment of obesity.
Assuntos
Histona Desmetilases com o Domínio Jumonji/metabolismo , Doenças Metabólicas/metabolismo , Obesidade/metabolismo , Adipócitos/metabolismo , Adipogenia/fisiologia , Tecido Adiposo/metabolismo , Animais , Peso Corporal/fisiologia , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/fisiologia , Epigênese Genética/fisiologia , Resistência à Insulina/fisiologia , Lipólise/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Oxirredução , Termogênese/fisiologiaRESUMO
Human norovirus is the leading cause of viral gastroenteritis worldwide. Rapid detection facilitates management of disease outbreaks, but field diagnosis is difficult to achieve due to the lack of reliable and portable methods. Recombinase polymerase amplification (RPA) is a robust isothermal amplification method that is capable of rapidly amplifying and detecting nucleic acids using simple equipment. In this study, RPA combined with lateral flow (LF) strips specific for human genogroup II (GII) noroviruses was established and evaluated. The assay specifically detects purified GII noroviruses as well as RNA in boiled human stool samples, with a sensitivity of 50 norovirus genome copies per reaction. The whole detection procedure of the one-step RT-RPA-LF is completed within 20 min, which is eight times faster than that of the standard real-time RT-PCR. The RT-RPA-LF method described here is suitable for rapid field diagnosis of all GII noroviruses in human stool samples.
Assuntos
Infecções por Caliciviridae/diagnóstico , Norovirus/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Infecções por Caliciviridae/genética , Fezes/virologia , Humanos , Norovirus/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Recombinases/química , Sensibilidade e EspecificidadeRESUMO
Histone modifications play important roles in regulating DNA-based biological processes. Of the modified sites, histone H3 lysine 56 (H3K56) is unique in that it lies within the globular core domain near the entry-exit sites of the nucleosomal DNA superhelix and its acetylation state in yeast is a marker for newly synthesized histones in transcription, DNA repair, and DNA replication. We now report the presence of H3K56 monomethylation (H3K56me1) in mammalian cells and find that the histone lysine methytransferase G9a/KMT1C is required for H3K56me1 both in vivo and in vitro. We also find that disruption of G9a or H3K56 impairs DNA replication. Furthermore, H3K56me1 associates with the replication processivity factor PCNA primarily in G1 phase of the cell cycle and, directly, in vitro. These results find H3K56me1 in mammals and indicate a role for H3K56me1 as a chromatin docking site for PCNA prior to its function in DNA replication.
Assuntos
Replicação do DNA/fisiologia , Fase G1/fisiologia , Histonas/metabolismo , Nucleossomos/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Células HEK293 , Células HeLa , Histonas/genética , Humanos , Lisina/genética , Lisina/metabolismo , Metilação , Nucleossomos/genética , Antígeno Nuclear de Célula em Proliferação/genéticaRESUMO
The development of therapies for human smallpox is needed due to the increasing concern over the potential use of smallpox virus as a biological weapon. Here, we report a high-throughput screening for anti-smallpox virus drugs from a 767-small-molecule library, employing two vaccinia virus (VACV) strains containing firefly luciferase (VTT-Fluc and VG9-Fluc) as surrogate viruses. Using an eight-point dose response format assay, 26 compounds of different pharmacological classes were identified with in vitro anti-VACV activities. Mycophenolate mofetil (MMF) and tranilast (TRA) were detected to possess the highest anti-VACV potency (selectivity index values of >334 and >74, respectively); they could inhibit VTT-Fluc replication in nude mice at 5 days post-infection by 99% (10 mg/kg, P < .01) and 59% (45 mg/kg, P = .01), respectively, as indicated by bioluminescent intensity. In conclusion, MMF and TRA are promising anti-smallpox virus candidates for further optimization and repurposing for use in clinical practice.
Assuntos
Antivirais/farmacologia , Reposicionamento de Medicamentos , Ensaios de Triagem em Larga Escala , Bibliotecas de Moléculas Pequenas/farmacologia , Vaccinia virus/efeitos dos fármacos , Animais , Linhagem Celular , Chlorocebus aethiops , Aprovação de Drogas , Descoberta de Drogas , Feminino , Camundongos , Camundongos Nus , Varíola/tratamento farmacológico , Vacínia/tratamento farmacológico , Células VeroRESUMO
JE vaccination is the most effective and economical method of preventing JE. A live attenuated JE vaccine has been widely used in many countries since 1989, playing an important role in controlling JE outbreaks. However, whether the large-scale use of the live attenuated JE vaccine will lead to the dissemination of the vaccine virus in the environment and whether reversion of the neuroattenuation of the virus will occur during the transmission process remain major concerns for some researchers. To evaluate the transmission of a live attenuated JEV vaccine in mosquitoes and hosts, JE SA14-14-2 attenuated vaccine virus was intrathoracically (i.t.) inoculated into Culex tritaeniorhynchus, a native vector. Subsequently, virus harvested from inoculated mosquitoes was inoculated into pigs, a mammalian reservoir. The virus was isolated from the pigs and passaged once again in Culex tritaeniorhynchus. The genome sequences and virulence of the passaged viruses were then investigated. While a few nucleotide substitutions occurred during passaging, there was no change in the encoded amino acids. After intracerebral (i.c.) inoculation of mice with the vaccine, no pathological effects were observed. In addition, virus virulence remained low after inoculation of suckling mouse brains. These results indicate that vaccination of individuals with the live vaccine will not result in transmission of the live SA14-14-2 vaccine virus through mosquito biting and virus amplified in pigs.
Assuntos
Vírus da Encefalite Japonesa (Espécie)/imunologia , Encefalite Japonesa , Vacinas contra Encefalite Japonesa/imunologia , Animais , Linhagem Celular , Cricetinae , Culex/imunologia , Culex/virologia , Encefalite Japonesa/imunologia , Encefalite Japonesa/prevenção & controle , Feminino , Vacinas contra Encefalite Japonesa/efeitos adversos , Masculino , Camundongos , Suínos , Vacinas AtenuadasRESUMO
A pair of nested PCR universal primers (NGIOF and NGIOR) specific for genogroup I (GI) noroviruses was designed based on all GI sequences available in public databases. The primers were evaluated for their specificity, sensitivity and coverage, which demonstrate their reliable performance upon detection of GI noroviruses in oysters.
Assuntos
Primers do DNA/metabolismo , Norovirus/genética , Norovirus/isolamento & purificação , Ostreidae/virologia , Reação em Cadeia da Polimerase/métodos , Animais , Simulação por Computador , HumanosRESUMO
Stimulator of interferon genes (STING) is an important regulator of the innate immune response to cytoplasmic DNA. However, regulation of STING itself is largely unknown. Here, we show that STING transcription is induced by innate immune activators, such as cyclic dinucleotides (CDNs), through an IFNAR1- and STAT1-dependent pathway. We also identify a STAT1 binding site in the STING promoter that contributes to the activation of STING transcription. Furthermore, we show that induction of STING mediates the positive feedback regulation of CDN-triggered IFN-I. Thus, our study demonstrates that STING is an interferon-stimulated gene (ISG) and its induction is crucial for the IFN-I positive feedback loop.
Assuntos
Interferon Tipo I/metabolismo , Interferons/metabolismo , Proteínas de Membrana/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Imunidade Inata/genética , Interferon Tipo I/genética , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Regiões Promotoras Genéticas/genética , Receptor de Interferon alfa e beta/genética , Receptor de Interferon alfa e beta/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismoRESUMO
A rapid and sensitive AHPND-RPA assay was developed for the specific detection of the AHPND-causing Vibrio owensii. The AHPND-RPA detected as few as 2 copies per reaction in 9.02 ± 0.66 min at 39 °C, and showed 100% positive predictive value and negative predictive value for AHPND diagnosis.
Assuntos
Doenças dos Animais/diagnóstico , Alimentos Marinhos/microbiologia , Vibrio/genética , Vibrio/isolamento & purificação , Doenças dos Animais/genética , Doenças dos Animais/microbiologia , Animais , Hepatopâncreas/microbiologia , Hepatopâncreas/patologia , Interações Hospedeiro-Patógeno/genética , Vibrio/patogenicidadeRESUMO
The genome sequence of a rare recombinant norovirus (NoV) genotype obtained from clinical samples in China was determined using one-step reverse transcription PCR. It was identified as the GII.P7/GII.6 genotype using both phylogenetic and SimPlot analyses. A high degree of variability was observed in the P2 subdomain, especially in the B-loop structure. The recombination breakpoints of all available GII.P7/GII.6 strains were mapped to two different positions within the RdRp region, both of which were at least 40 nt upstream of the overlap of ORF1 and 2. The GII.P7/GII.6 genotype appears to have been circulating in Asia for at least 10 years.
Assuntos
Infecções por Caliciviridae/virologia , Gastroenterite/virologia , Genoma Viral , Norovirus/genética , Adulto , China , Clonagem Molecular , Fezes/virologia , Genótipo , Humanos , Masculino , Norovirus/isolamento & purificação , Filogenia , Recombinação Genética , Análise de Sequência de DNARESUMO
Rapid and robust induction of type I IFN (IFN-I) is a critical event in host antiviral innate immune response. It has been well demonstrated that cyclic GMP-AMP (cGAMP) synthase (cGAS) plays an important role in sensing cytosolic DNA and triggering STING dependent signaling to induce IFN-I. However, it is largely unknown how cGAS itself is regulated during pathogen infection and IFN-I production. In this study, we show that pattern recognition receptor (PRR) ligands, including lipid A, LPS, poly(I:C), poly(dA:dT), and cGAMP, induce cGAS expression in an IFN-I-dependent manner in both mouse and human macrophages. Further experiments indicated that cGAS is an IFN-stimulated gene (ISG), and two adjacent IFN-sensitive response elements (ISREs) in the promoter region of cGAS mediate the induction of cGAS by IFN-I. Additionally, we show that optimal production of IFN-ß triggered by poly (dA:dT) or HSV-1 requires IFNAR signaling. Knockdown of the constitutively expressed DNA sensor DDX41 attenuates poly(dA:dT)-triggered IFN-ß production and cGAS induction. By analyzing the dynamic expression of poly(dA:dT)-induced IFN-ß and cGAS transcripts, we have found that induction of IFN-ß is earlier than cGAS. Furthermore, we have provided evidence that induction of cGAS by IFN-I meditates the subsequent positive feedback regulation of DNA-triggered IFN-I production. Thus, our study not only provides a novel mechanism of modulating cGAS expression, but also adds another layer of regulation in DNA-triggered IFN-I production by induction of cGAS.
Assuntos
Imunidade Inata/imunologia , Interferon Tipo I/biossíntese , Macrófagos/imunologia , Nucleotidiltransferases/imunologia , Animais , Linhagem Celular , Imunoprecipitação da Cromatina , Ensaio de Imunoadsorção Enzimática , Retroalimentação Fisiológica , Humanos , Immunoblotting , Interferon Tipo I/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nucleotidiltransferases/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase em Tempo RealRESUMO
To develop a potential dengue vaccine candidate, a full-length cDNA clone of a novel chimeric virus was constructed using recombinant DNA technology, with Japanese encephalitis virus (JEV) vaccine strain SA14-14-2 as the backbone, with its premembrane (prM) and envelope (E) genes substituted by their counterparts from dengue virus type 1 (DENV1). The chimeric virus (JEV/DENV1) was successfully recovered from primary hamster kidney (PHK) cells by transfection with the in vitro transcription products of JEV/DENV1 cDNA and was identified by complete genome sequencing and immunofluorescent staining. No neuroinvasiveness of this chimeric virus was observed in mice inoculated by the subcutaneous route (s.c.) or by the intraperitoneal route (i.p.), while some neurovirulence was displayed in mice that were inoculated directly by the intracerebral route (i.c.). The chimeric virus was able to stimulate high-titer production of antibodies against DENV1 and provided protection against lethal challenge with neuroadapted dengue virus in mice. These results suggest that the chimeric virus is a promising dengue vaccine candidate.