Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 761
Filtrar
1.
Front Cell Infect Microbiol ; 14: 1407064, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39119295

RESUMO

Background & aims: HBV infection initiates autoimmune responses, leading to autoantibody generation. This research explores the role of autoantibodies in HBV-related Acute-on-Chronic Liver Failure (ACLF), offering novel perspectives for clinical management. Method: We applied immunoprecipitation and iTRAQ techniques to screen for autoantibodies in serum from HBV-related cirrhosis patients and conducted detection with conformation- stabilizing ELISA in a cohort of 238 HBV-infected individuals and 49 health controls. Our results were validated in a retrospective cohort comprising 106 ACLF patients and further assessed through immunohistochemical analysis in liver tissues from an additional 10 ACLF cases. Results: Utilizing iTRAQ, we identified Argonaute1-3 autoantibodies (AGO-Abs) in this research. AGO2-Abs notably increased in cirrhosis, decompensation, and further in ACLF, unlike AGO1-Abs and AGO3-Abs. This reflects disease severity correlation. Logistic regression and COX models confirmed AGO2-Abs as independent prognostic indicators for decompensated liver cirrhosis (DLC) and ACLF. In the ROC analysis, AGO2-Abs showed significant diagnostic value for predicting 28- and 90-day mortality (AUROC = 0.853 and 0.854, respectively). Furthermore, combining AGO2-Abs with the Child-Pugh, MELD, and AARC scores significantly improved their predictive accuracy (P < 0.05). Kaplan-Meier analysis showed poorer survival for AGO2-Abs levels above 99.14µg/ml. These findings were supported by a retrospective validation cohort. Additionally, immunohistochemistry revealed band-like AGO2 expression in periportal liver areas, with AGO2-Abs levels correlating with total bilirubin, indicating a potential role in exacerbating liver damage through periportal functions. Conclusions: AGO2-Abs is a robust biomarker for predicting the mortality of patients with HBV-related ACLF.


Assuntos
Insuficiência Hepática Crônica Agudizada , Proteínas Argonautas , Autoanticorpos , Biomarcadores , Cirrose Hepática , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência Hepática Crônica Agudizada/mortalidade , Insuficiência Hepática Crônica Agudizada/imunologia , Autoanticorpos/sangue , Autoanticorpos/imunologia , Biomarcadores/sangue , Hepatite B Crônica/complicações , Hepatite B Crônica/mortalidade , Hepatite B Crônica/imunologia , Fígado/patologia , Cirrose Hepática/mortalidade , Cirrose Hepática/imunologia , Prognóstico , Estudos Retrospectivos , Curva ROC
2.
Poult Sci ; 103(10): 104141, 2024 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-39137501

RESUMO

Rapid and accurate detection of goose parvovirus (GPV) is crucial for controlling outbreaks and mitigating their economic impact on the poultry industry. This study introduces recombinase polymerase amplification combined with the Pyrococcus furiosus argonaute (RPA-PfAgo) system, a novel diagnostic platform designed to address the limitations of traditional GPV detection methods. Capitalizing on the rapid DNA amplification of RPA and stringent nucleic acid cleavage by the PfAgo protein, the RPA-PfAgo system offers high specificity and sensitivity in detecting GPV. Our optimization efforts included primer and probe configurations, reaction parameters, and guided DNA selection, culminating in a detection threshold of 102 GPV DNA copies per microlitre. The specificity of the proposed method was rigorously validated against a spectrum of avian pathogens. Clinical application to lung tissues from GPV-infected geese yielded a detection concordance of 100%, surpassing that of qPCR and PCR in both rapidity and operational simplicity. The RPA-PfAgo system has emerged as a revolutionary diagnostic modality for managing this disease, as it is a promising rapid, economical, and onsite GPV detection method amenable to integration into broad-scale disease surveillance frameworks. Future explorations will extend the applicability of this method to diverse avian diseases and assess its field utility across various epidemiological landscapes.

3.
Front Cell Infect Microbiol ; 14: 1419949, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39119294

RESUMO

Human respiratory syncytial virus (HRSV) is the most prevalent pathogen contributing to acute respiratory tract infections (ARTI) in infants and young children and can lead to significant financial and medical costs. Here, we developed a simultaneous, dual-gene and ultrasensitive detection system for typing HRSV within 60 minutes that needs only minimum laboratory support. Briefly, multiplex integrating reverse transcription-recombinase polymerase amplification (RT-RPA) was performed with viral RNA extracted from nasopharyngeal swabs as a template for the amplification of the specific regions of subtypes A (HRSVA) and B (HRSVB) of HRSV. Next, the Pyrococcus furiosus Argonaute (PfAgo) protein utilizes small 5'-phosphorylated DNA guides to cleave target sequences and produce fluorophore signals (FAM and ROX). Compared with the traditional gold standard (RT-qPCR) and direct immunofluorescence assay (DFA), this method has the additional advantages of easy operation, efficiency and sensitivity, with a limit of detection (LOD) of 1 copy/µL. In terms of clinical sample validation, the diagnostic accuracy of the method for determining the HRSVA and HRSVB infection was greater than 95%. This technique provides a reliable point-of-care (POC) testing for the diagnosis of HRSV-induced ARTI in children and for outbreak management, especially in resource-limited settings.


Assuntos
RNA Viral , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Sensibilidade e Especificidade , Humanos , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/isolamento & purificação , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/virologia , RNA Viral/genética , Lactente , Pyrococcus furiosus/genética , Pyrococcus furiosus/isolamento & purificação , Proteínas Argonautas/genética , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Limite de Detecção , Nasofaringe/virologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/virologia , Pré-Escolar
4.
Food Chem ; 460(Pt 3): 140615, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39126941

RESUMO

Molecular diagnosis of foodborne methicillin-resistant Staphylococcus aureus (MRSA) is crucial for controlling its dissemination and ensuring food safety. However, existing genetic methods are limited by susceptibility to aerosol contamination and restricted to single-gene detection. Herein, a fluorescent biosensor employing fluorescence-encoded microspheres and Argonaute-mediated decoding is developed, enabling ultrasensitive, accurate, and duplex detection of MRSA genes. This assay utilizes a target-triggered polymerization/nicking reaction to cyclically produce specific guide DNA, guiding Argonaute protein to site-specifically cleave the molecular beacon on the microsphere, thereby decoding a fluorescent signal. Notably, the fluorescence-encoded microsphere, designed via on-tetrahedron rolling circle amplification, achieves high fluorescence loadings in a unit area. This biosensor demonstrates simultaneous detection of two unamplified MRSA genes, mecA and femA, at concentrations as low as 0.63 fM and 0.48 fM, respectively. Moreover, the method exhibited excellent recoveries in milk, egg, and pork samples ranging from 73% to 112%, highlighting its practicability in real scenarios.

5.
Int J Biol Macromol ; 278(Pt 2): 134755, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39147338

RESUMO

With the attributes of high sensitivity, single-base resolution, multiplex detection capability, and programmability upon nucleic acid recognition, Argonaute (Ago)-based biosensing assays are increasingly recognized as one of the most promising tools for precise identification and quantification of target analytes. Employed as highly specific sequence recognition elements of these robust diagnostic methods, Agos are revolutionizing how nucleic acid targets are detected. A systematic and comprehensive summary of this emerging and rapid-advancing technology is necessary to give play to the potential of Ago-based biosensing assays. The structure and function of Agos were briefly overviewed at the beginning of the work, followed by a review of the recent advancements in employing Agos sensing for detecting various targets with a comprehensive analysis such as viruses, tumor biomarkers, pathogens, mycoplasma, and parasite. The significance and benefits of these platforms were then deliberated. In addition, the authors shared subjective viewpoints on the existing challenges and offered relevant guidance for the future progress of Agos assays. Finally, the future research outlook regarding Ago-based sensing in this field was also outlined. As such, this review is expected to offer valuable information and fresh perspectives for a broader group of researchers.

6.
Trends Biotechnol ; 2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39034177

RESUMO

CRISPR/Cas and Argonaute (Ago) proteins, which target specific nucleic acid sequences, can be applied as diagnostic tools. Despite high specificity and efficiency, achieving sensitive detection often necessitates a preamplification step that involves opening the lid and multistep operation, which may elevate the risk of contamination and prove inadequate for point-of-care testing. Hence, various one-pot detection strategies have been developed that enable preamplification and sensing in a single operation. We outline the challenges of one-pot detection with Cas and Ago proteins, present several main implementation strategies, and discuss future prospects. This review offers comprehensive insights into this vital field and explores potential improvements to detection methods that will be beneficial for human health.

7.
Virus Res ; 348: 199436, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-38996815

RESUMO

RNA silencing is a prominent antiviral defense mechanism in plants. When infected with a virus, RNA silencing-deficient plants tend to show exacerbated symptoms along with increased virus accumulation. However, how symptoms are exacerbated is little understood. Here, we investigated the role of the copper chaperon for superoxide dismutase (CCS) 1, in systemic necrosis observed in Argonaute (AGO)2-silenced tomato plants infected with potato virus X (PVX). While infection with the UK3 strain of PVX induced mosaic symptoms in tomato plants, systemic necrosis occurred when AGO2 was silenced. The CCS1 mRNA level was reduced and micro RNA398 (miR398), which potentially target CCS1, was increased in AGO2-knockdown tomato plants infected with PVX-UK3. Ectopic expression of CCS1 using recombinant PVX attenuated necrosis, suggesting that CCS1 alleviates systemic necrosis by activating superoxide dismutases to scavenge reactive oxygen species. Previous reports have indicated a decrease in the levels of CCS1 and superoxide dismutases along with an increased level of miR398 in plants infected with other viruses and viroids, and thus might represent shared regulatory mechanisms that exacerbate symptoms in these plants.

8.
Mol Cell ; 84(15): 2918-2934.e11, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39025072

RESUMO

The RNA-induced silencing complex (RISC), which powers RNA interference (RNAi), consists of a guide RNA and an Argonaute protein that slices target RNAs complementary to the guide. We find that, for different guide-RNA sequences, slicing rates of perfectly complementary bound targets can be surprisingly different (>250-fold range), and that faster slicing confers better knockdown in cells. Nucleotide sequence identities at guide-RNA positions 7, 10, and 17 underlie much of this variation in slicing rates. Analysis of one of these determinants implicates a structural distortion at guide nucleotides 6-7 in promoting slicing. Moreover, slicing directed by different guide sequences has an unanticipated, 600-fold range in 3'-mismatch tolerance, attributable to guides with weak (AU-rich) central pairing requiring extensive 3' complementarity (pairing beyond position 16) to more fully populate the slicing-competent conformation. Together, our analyses identify sequence determinants of RISC activity and provide biochemical and conformational rationale for their action.


Assuntos
Proteínas Argonautas , Conformação de Ácido Nucleico , RNA Guia de Sistemas CRISPR-Cas , Complexo de Inativação Induzido por RNA , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Proteínas Argonautas/química , Humanos , Complexo de Inativação Induzido por RNA/metabolismo , Complexo de Inativação Induzido por RNA/genética , Complexo de Inativação Induzido por RNA/química , Cinética , RNA Guia de Sistemas CRISPR-Cas/genética , RNA Guia de Sistemas CRISPR-Cas/metabolismo , Interferência de RNA , Sequência de Bases , Células HEK293
9.
Plant Sci ; 347: 112176, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38971466

RESUMO

RNA silencing, a conserved gene regulatory mechanism, is critical for host resistance to viruses. Liquid-liquid phase separation (LLPS) is an important mechanism in regulating various biological processes. Emerging studies suggest RNA helicases play important roles in microRNA (miRNA) production through LLPS. In this study, we investigated the functional role of RNA helicase 20 (RH20), a DDX5 homolog in Arabidopsis thaliana, in RNA silencing and plant resistance to viruses. Our findings reveal that RH20 localizes in both the cytoplasm and nucleus, with puncta formation in the cytoplasm exhibiting liquid-liquid phase separation behavior. We demonstrate that RH20 plays positive roles in plant immunity against viruses. Further study showed that RH20 interacts with Argonaute 2 (AGO2), a key component of the RNA silencing pathway. Moreover, RH20 promotes the accumulation of both endogenous and exogenous small RNAs (sRNAs). Overall, our study identifies RH20 as a novel phase separation protein that interacting with AGO2, influencing sRNAs accumulation, and enhancing plant resistance to viruses.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Argonautas , Resistência à Doença , Doenças das Plantas , Arabidopsis/genética , Arabidopsis/virologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Doenças das Plantas/virologia , Resistência à Doença/genética , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , RNA Helicases/metabolismo , RNA Helicases/genética , Imunidade Vegetal/genética , Interferência de RNA , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , MicroRNAs/metabolismo
10.
Epigenomes ; 8(3)2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-39051182

RESUMO

Human tumors progress in part by accumulating epigenetic alterations, which include gains and losses of DNA methylation in different parts of the cancer cell genome. Recent work has revealed a link between these two opposite alterations by showing that DNA hypomethylation in tumors can induce the expression of transcripts that overlap downstream gene promoters and thereby induce their hypermethylation. Preliminary in silico evidence prompted us to investigate if this mechanism applies to the locus harboring AGO1, a gene that plays a central role in miRNA biogenesis and RNA interference. Inspection of public RNA-Seq datasets and RT-qPCR experiments show that an alternative transcript starting 13.4 kb upstream of AGO1 (AGO1-V2) is expressed specifically in testicular germ cells, and becomes aberrantly activated in different types of tumors, particularly in tumors of the esophagus, stomach, and lung. This expression pattern classifies AGO1-V2 into the group of "Cancer-Germline" (CG) genes. Analysis of transcriptomic and methylomic datasets provided evidence that transcriptional activation of AGO1-V2 depends on DNA demethylation of its promoter region. Western blot experiments revealed that AGO1-V2 encodes a shortened isoform of AGO1, corresponding to a truncation of 75 aa in the N-terminal domain, and which we therefore referred to as "∆NAGO1". Interestingly, significant correlations between hypomethylation/activation of AGO1-V2 and hypermethylation/repression of AGO1 were observed upon examination of tumor cell lines and tissue datasets. Overall, our study reveals the existence of a process of interdependent epigenetic alterations in the AGO1 locus, which promotes swapping between two AGO1 protein-coding mRNA isoforms in tumors.

11.
Investig Clin Urol ; 65(4): 400-410, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38978220

RESUMO

PURPOSE: To determine whether the overexpression of the Argonaute RNA-induced silencing complex catalytic component 2 (Ago2) improves erectile function in mice after cavernous nerve injury (CNI). MATERIALS AND METHODS: Lentiviruses containing Ago2 open reading frame (ORF) mouse clone (Ago2 O/E) were used to overexpress Ago2, and lentiviruses ORF negative control particles (NC) were used as a negative control. Three days before preparing the CNI model, we injected lentiviruses into the penises of 8-week-old male C57BL/6 mice. Animals were then divided into four groups: the sham operation control group and the CNI+phosphate-buffered saline, CNI+NC, and CNI+Ago2 O/E groups. One week later, erectile function was assessed by electrically stimulating cavernous nerves bilaterally and obtaining intracavernous pressure parameters. Penile tissue was also collected for molecular mechanism studies. RESULTS: Ago2 overexpression improved erectile function in mice after CNI-induced erectile dysfunction (ED). Immunofluorescence staining and Western blot analysis showed that under Ago2 overexpressing conditions, the contents of endothelial cells, pericytes, and neuronal cells increased in the penile tissues of CNI mice, and this was attributed to reduced apoptosis and ROS production. In addition, we also found that Ago2 overexpression could restore penile mitochondrial function, thereby improving erectile function in CNI-induced ED mice. CONCLUSIONS: Our findings demonstrate that Ago2 overexpression can reduce penile cell apoptosis, restore penile mitochondrial function, and improve erectile function in CNI-induced ED mice.


Assuntos
Apoptose , Proteínas Argonautas , Modelos Animais de Doenças , Disfunção Erétil , Camundongos Endogâmicos C57BL , Mitocôndrias , Ereção Peniana , Pênis , Animais , Masculino , Pênis/inervação , Disfunção Erétil/etiologia , Camundongos , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Mitocôndrias/metabolismo , Ereção Peniana/fisiologia , Traumatismos dos Nervos Periféricos/complicações
12.
Plant Cell Physiol ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38988198

RESUMO

As a model plant for bryophytes, Marchantia polymorpha offers insights into the role of RNA silencing in aiding early land plants navigate the challenges posed by high-temperature environments. Genomic analysis revealed unique ARGONAUTE1 ortholog gene (MpAGO1) in M. polymorpha that is regulated by two species-specific microRNAs (miRNAs), miR11707.1 and miR11707.2. Comparative studies of small RNA profiles from M. polymorpha cellular and MpAGO1 immunoprecipitation (MpAGO1-IP) profiles at various temperatures, along with analyses of Arabidopsis AGO1 (AtAGO1), revealed that MpAGO1 has a low-selectivity for a diverse range of small RNA species than AtAGO1. Protein structural comparisons revealed no discernible differences in the MID domains of MpAGO1 and AtAGO1, suggesting the complexity of miRNA species specificity and necessitating further exploration. Small RNA profiling and size exclusion chromatography have pinpointed a subset of M. polymorpha miRNAs, notably miR11707, that remain in free form within the cell at 22°C but are loaded into MpAGO1 at 28°C to engage in RNA silencing. Investigations into the mir11707 gene editing (mir11707ge) mutants provided evidence of the regulation of miR11707 in MpAGO1. Notably, while MpAGO1 mRNA expression decreases at 28°C, the stability of the MpAGO1 protein and its associated miRNAs is essential for enhancing the RISC activity, revealing the importance of RNA silencing in enabling M. polymorpha to survive thermal stress. This study advances our understanding of RNA silencing in bryophytes and provides groundbreaking insights into the evolutionary resilience of land plants to climatic adversities.

13.
Cell Rep ; 43(7): 114391, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38923459

RESUMO

Inhibition of nucleic acid targets is mediated by Argonaute (Ago) proteins guided by RNA or DNA. Although the mechanisms underpinning the functions of eukaryotic and "long" prokaryotic Ago proteins (pAgos) are well understood, those for short pAgos remain enigmatic. Here, we determine two cryoelectron microscopy structures of short pAgos in association with the NADase-domain-containing protein Sir2-APAZ from Geobacter sulfurreducens (GsSir2/Ago): the guide RNA-target DNA-loaded GsSir2/Ago quaternary complex (2.58 Å) and the dimer of the quaternary complex (2.93Å). These structures show that the nucleic acid binding causes profound conformational changes that result in disorder or partial dissociation of the Sir2 domain, suggesting that it adopts a NADase-active conformation. Subsequently, two RNA-/DNA-loaded GsSir2/Ago complexes form a dimer through their MID domains, further enhancing NADase activity through synergistic effects. The findings provide a structural basis for short-pAgo-mediated defense against invading nucleic acids.


Assuntos
Proteínas Argonautas , Proteínas Argonautas/metabolismo , Proteínas Argonautas/química , Geobacter/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Sirtuína 2/metabolismo , Multimerização Proteica , Ligação Proteica , Microscopia Crioeletrônica , Ativação Enzimática , Modelos Moleculares , Ácidos Nucleicos/metabolismo
14.
Fish Shellfish Immunol ; 151: 109693, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38878913

RESUMO

Argonaute proteins are key constituents of small RNA-guided regulatory pathways. In crustaceans, members of the AGO subfamily of Argonaute proteins that play vital roles in immune defense are well studied, while proteins of the PIWI subfamily are less established. PmAgo4 of the black tiger shrimp, Penaeus monodon, though phylogenetically clustered with the AGO subfamily, has distinctive roles of the PIWI subfamily in safeguarding the genome from transposon invasion and controlling germ cell development. This study explored a molecular mechanism by which PmAgo4 regulates transposon expression in the shrimp germline. PmAgo4-associated small RNAs were co-immunoprecipitated from shrimp testis lysate using a PmAgo4-specific polyclonal antibody. RNA-seq revealed a majority of 26-27 nt long small RNAs in the PmAgo4-IP fraction suggesting that PmAgo4 is predominantly associated with piRNAs. Mapping of these piRNAs on nucleotide sequences of two gypsy and a mariner-like transposons of P. monodon suggested that most piRNAs were originated from the antisense strand of transposons. Suppression of PmAgo4 expression by a specific dsRNA elevated the expression levels of the three transposons while decreasing the levels of transposon-related piRNAs. Taken together, these results imply that PmAgo4 exerts its suppressive function on transposons by controlling the biogenesis of transposon-related piRNAs and thus, provides a defense mechanism against transposon invasion in shrimp germline cells.


Assuntos
Proteínas Argonautas , Elementos de DNA Transponíveis , Penaeidae , RNA Interferente Pequeno , Animais , Penaeidae/imunologia , Penaeidae/genética , Elementos de DNA Transponíveis/genética , RNA Interferente Pequeno/genética , Proteínas Argonautas/genética , Proteínas Argonautas/imunologia , Proteínas Argonautas/metabolismo , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/imunologia , Proteínas de Artrópodes/química , Imunidade Inata/genética , Regulação da Expressão Gênica/imunologia , RNA de Interação com Piwi
15.
J Integr Plant Biol ; 66(8): 1620-1638, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38860597

RESUMO

The development of flowers in soybean (Glycine max) is essential for determining the yield potential of the plant. Gene silencing pathways are involved in modulating flower development, but their full elucidation is still incomplete. Here, we conducted a forward genetic screen and identified an abnormal flower mutant, deformed floral bud1-1 (Gmdfb1-1), in soybean. We mapped and identified the causal gene, which encodes a member of the armadillo (ARM)-repeat superfamily. Using small RNA sequencing (sRNA-seq), we found an abnormal accumulation of small interfering RNAs (siRNAs) and microRNA (miRNAs) in the Gmdfb1 mutants. We further demonstrated that GmDFB1 interacts with the RNA exosome cofactor SUPER KILLER7 (GmSKI7). Additionally, GmDFB1 interacts with the PIWI domain of ARGONAUTE 1 (GmAGO1) to inhibit the cleavage efficiency on the target genes of sRNAs. The enhanced gene silencing mediated by siRNA and miRNA in the Gmdfb1 mutants leads to the downregulation of their target genes associated with flower development. This study revealed the crucial role of GmDFB1 in regulating floral organ identity in soybean probably by participating in two distinct gene silencing pathways.


Assuntos
Flores , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Glycine max , MicroRNAs , Proteínas de Plantas , RNA Interferente Pequeno , Glycine max/genética , Glycine max/crescimento & desenvolvimento , Glycine max/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/genética , Mutação/genética
16.
Proc Natl Acad Sci U S A ; 121(25): e2322765121, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38865263

RESUMO

Antiviral RNA interference (RNAi) is conserved from yeasts to mammals. Dicer recognizes and cleaves virus-derived double-stranded RNA (dsRNA) and/or structured single-stranded RNA (ssRNA) into small-interfering RNAs, which guide effector Argonaute to homologous viral RNAs for digestion and inhibit virus replication. Thus, Argonaute is believed to be essential for antiviral RNAi. Here, we show Argonaute-independent, Dicer-dependent antiviral defense against dsRNA viruses using Cryphonectria parasitica (chestnut blight fungus), which is a model filamentous ascomycetous fungus and hosts a variety of viruses. The fungus has two dicer-like genes (dcl1 and dcl2) and four argonaute-like genes (agl1 to agl4). We prepared a suite of single to quadruple agl knockout mutants with or without dcl disruption. We tested these mutants for antiviral activities against diverse dsRNA viruses and ssRNA viruses. Although both DCL2 and AGL2 worked as antiviral players against some RNA viruses, DCL2 without argonaute was sufficient to block the replication of other RNA viruses. Overall, these results indicate the existence of a Dicer-alone defense and different degrees of susceptibility to it among RNA viruses. We discuss what determines the great difference in susceptibility to the Dicer-only defense.


Assuntos
Vírus de RNA , Ribonuclease III , Ribonuclease III/metabolismo , Ribonuclease III/genética , Vírus de RNA/imunologia , Vírus de RNA/genética , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Ascomicetos/virologia , Interferência de RNA , Replicação Viral/genética , RNA Viral/metabolismo , RNA Viral/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , RNA de Cadeia Dupla/metabolismo
17.
Front Immunol ; 15: 1366531, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38887290

RESUMO

Aquaporin-4 antibodies (AQP4-Abs) are a diagnostic marker for patients with a demyelinating disease called neuromyelitis optica spectrum disorder (NMOSD). Anti-Argonaute antibodies (AGO-Abs) present as potential biomarkers of the overlap syndrome between NMOSD and other autoimmune diseases. In this paper, we present the case of an adult woman with numbness, tingling, and burning sensations in her arms and subsequent bilateral internuclear ophthalmoplegia. Brain-cervical-thoracic magnetic resonance imaging (MRI) showed T2 hyperintensities in the dorsal brainstem and around the midbrain aqueduct and longitudinally transverse myelitis with homogeneous enhancement on gadolinium-enhanced MRI. The contemporaneous detection of AQP4- and AGO-Abs led to a definite diagnosis of overlap syndrome of NMOSD with AGO-Abs. The patient was treated with immunosuppressive agents, including corticosteroids and immunoglobulins, and achieved remission. This case highlights a novel phenotype of NMOSD with AGO-Abs overlap syndrome, which presents with relapsing brainstem syndrome and longitudinally extensive myelitis with acute severe neurological involvement. The promising prognosis of the disease could serve as a distinct clinical profile. Broad screening for antibodies against central nervous system autoimmune antigens is recommended in suspected patients with limited or atypical clinical manifestations.


Assuntos
Autoanticorpos , Neuromielite Óptica , Humanos , Neuromielite Óptica/imunologia , Neuromielite Óptica/diagnóstico , Neuromielite Óptica/tratamento farmacológico , Feminino , Autoanticorpos/imunologia , Autoanticorpos/sangue , Aquaporina 4/imunologia , Adulto , Biomarcadores , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Imunossupressores/uso terapêutico
18.
bioRxiv ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38766062

RESUMO

The RNA-induced silencing complex (RISC), which powers RNA interference (RNAi), consists of a guide RNA and an Argonaute protein that slices target RNAs complementary to the guide. We find that for different guide-RNA sequences, slicing rates of perfectly complementary, bound targets can be surprisingly different (>250-fold range), and that faster slicing confers better knockdown in cells. Nucleotide sequence identities at guide-RNA positions 7, 10, and 17 underlie much of this variation in slicing rates. Analysis of one of these determinants implicates a structural distortion at guide nucleotides 6-7 in promoting slicing. Moreover, slicing directed by different guide sequences has an unanticipated, 600-fold range in 3'-mismatch tolerance, attributable to guides with weak (AU-rich) central pairing requiring extensive 3' complementarity (pairing beyond position 16) to more fully populate the slicing-competent conformation. Together, our analyses identify sequence determinants of RISC activity and provide biochemical and conformational rationale for their action.

19.
Genome Biol Evol ; 16(5)2024 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-38713108

RESUMO

In animals, three main RNA interference mechanisms have been described so far, which respectively maturate three types of small noncoding RNAs (sncRNAs): miRNAs, piRNAs, and endo-siRNAs. The diversification of these mechanisms is deeply linked with the evolution of the Argonaute gene superfamily since each type of sncRNA is typically loaded by a specific Argonaute homolog. Moreover, other protein families play pivotal roles in the maturation of sncRNAs, like the DICER ribonuclease family, whose DICER1 and DICER2 paralogs maturate respectively miRNAs and endo-siRNAs. Within Metazoa, the distribution of these families has been only studied in major groups, and there are very few data for clades like Lophotrochozoa. Thus, we here inferred the evolutionary history of the animal Argonaute and DICER families including 43 lophotrochozoan species. Phylogenetic analyses along with newly sequenced sncRNA libraries suggested that in all Trochozoa, the proteins related to the endo-siRNA pathway have been lost, a part of them in some phyla (i.e. Nemertea, Bryozoa, Entoprocta), while all of them in all the others. On the contrary, early diverging phyla, Platyhelminthes and Syndermata, showed a complete endo-siRNA pathway. On the other hand, miRNAs were revealed the most conserved and ubiquitous mechanism of the metazoan RNA interference machinery, confirming their pivotal role in animal cell regulation.


Assuntos
Evolução Molecular , MicroRNAs , Filogenia , Interferência de RNA , Ribonuclease III , Animais , Ribonuclease III/genética , MicroRNAs/genética , RNA Interferente Pequeno/genética , Proteínas Argonautas/genética , Invertebrados/genética
20.
Gene ; 922: 148544, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-38734187

RESUMO

This study introduces an efficient RPA-PfAgo detection system for the MTHFR C677T polymorphism, proposing a potential strategy to simplify the genotyping process. By optimizing recombinase polymerase amplification (RPA) with Pyrococcus furiosus Argonaute (PfAgo) nucleases, we achieved DNA amplification at a constant temperature. The assay was fine-tuned through meticulous primer and guide DNA selection, with optimal conditions established at 2.0 µL of MgAc, a reaction temperature of 42 °C, and a 10-minute reaction time for RPA. Further optimization of the PfAgo cleavage assay revealed the ideal concentrations of MnCl2, guide DNA, molecular beacon probes, the PfAgo enzyme, and the RPA product to maximize sensitivity and specificity. Clinical validation of 20 samples showed 100% concordance with Sanger sequencing, confirming the method's precision. The RPA-PfAgo system is a promising tool for on-site genotyping, with broad applications in personalized medicine and disease prevention.


Assuntos
Técnicas de Genotipagem , Metilenotetra-Hidrofolato Redutase (NADPH2) , Humanos , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Técnicas de Genotipagem/métodos , Polimorfismo de Nucleotídeo Único , Pyrococcus furiosus/genética , Pyrococcus furiosus/enzimologia , Genótipo , Técnicas de Amplificação de Ácido Nucleico/métodos , Proteínas Argonautas/genética , Recombinases/metabolismo , Recombinases/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA