RESUMO
Connexins (Cxs) are transmembrane proteins which form hemichannels and gap junction channels at the plasma membrane. These channels allow the exchange of ions and molecules between the intra- and extracellular space and between cytoplasm of adjacent cells, respectively. The channel function of Cx assemblies has been extensively studied; however, "noncanonical" functions have emerged in the last few decades and have capture the attentions of many researchers, including the role of some Cxs as gene modulators or transcription factors. In this chapter, we describe a protocol to study the interaction of Cx46 with DNA in HeLa cells. These methods can facilitate understanding the role of Cxs in physiological processes and pathological mechanisms, including, for example, the contribution of Cx46 in maintaining stemness of glioma cancer stem cells.
Assuntos
Conexinas , Canais Iônicos , Humanos , Conexinas/genética , Conexinas/metabolismo , Células HeLa , Junções Comunicantes/metabolismo , DNA/genéticaRESUMO
Microtubule Organizing Centers (MTOC) are subcellular structures in eukaryotic cells where nucleation of microtubules (MTs) takes place and represents the filament's minus end. Their localization depends on the species, cell type, and cell cycle stage. Along the fungal kingdom, the Spindle Pole Body (SPB) in the nucleus (an equivalent to Centrosomes in animal cells) is the principal MTOC. Other MTOCs have been identified in filamentous fungi, such as the Spitzenkörper in the hyphal tips of Schizosaccharomyces pombe or the septal pore of Aspergillus nidulans. However, in the fungal-model organism Neurospora crassa, these alternative MTOCs have not been recognized. Here, we present a Mass spectrometry-based dataset of proteins interacting with four MTOC components of N. crassa tagged with fluorescent proteins: γ-Tubulin-sGFP (main nucleator at the SPB), MZT-1-sGFP (structural SPB microprotein), APS-2-dRFP (septal protein and recognized SPB component), and SPA-10-sGFP (septal MTOC protein). A WT and a cytosolic GFP expressing strain were included as controls. The protein interactors were pulled down by Co-IP1, using GFP-Magnetic agarose that captures recombinant GFP proteins (including GFP-derivatives) in their native state. Bounded proteins were separated by SDS-PAGE and identified by nano LC-MS/MS2. The protein annotation was done using the N. crassa protein database.
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Leptospirosis is a neglected disease of man and animals that affects nearly half a million people annually and causes considerable economic losses. Current human vaccines are inactivated whole-cell preparations (bacterins) of Leptospira spp. that provide strong homologous protection yet fail to induce a cross-protective immune response. Yearly boosters are required, and serious side-effects are frequently reported so the vaccine is licensed for use in humans in only a handful of countries. Novel universal vaccines require identification of conserved surface-exposed epitopes of leptospiral antigens. Outer membrane ß-barrel proteins (ßb-OMPs) meet these requirements and have been successfully used as vaccines for other diseases. We report the evaluation of 22 constructs containing protein fragments from 33 leptospiral ßb-OMPs, previously identified by reverse and structural vaccinology and cell-surface immunoprecipitation. Three-dimensional structures for each leptospiral ßb-OMP were predicted by I-TASSER. The surface-exposed epitopes were predicted using NetMHCII 2.2 and BepiPred 2.0. Recombinant constructs containing regions from one or more ßb-OMPs were cloned and expressed in Escherichia coli. IMAC-purified recombinant proteins were adsorbed to an aluminium hydroxide adjuvant to produce the vaccine formulations. Hamsters (4-6 weeks old) were vaccinated with 2 doses containing 50 - 125 µg of recombinant protein, with a 14-day interval between doses. Immunoprotection was evaluated in the hamster model of leptospirosis against a homologous challenge (10 - 20× ED50) with L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni strain Fiocruz L1-130. Of the vaccine formulations, 20/22 were immunogenic and induced significant humoral immune responses (IgG) prior to challenge. Four constructs induced significant protection (100%, P < 0.001) and sterilizing immunity in two independent experiments, however, this was not reproducible in subsequent evaluations (0 - 33.3% protection, P > 0.05). The lack of reproducibility seen in these challenge experiments and in other reports in the literature, together with the lack of immune correlates and commercially available reagents to characterize the immune response, suggest that the hamster may not be the ideal model for evaluation of leptospirosis vaccines and highlight the need for evaluation of alternative models, such as the mouse.
Assuntos
Leptospira , Leptospirose , Cricetinae , Humanos , Camundongos , Animais , Hidróxido de Alumínio , Reprodutibilidade dos Testes , Leptospirose/prevenção & controle , Vacinas Bacterianas , Antígenos de Bactérias/genética , Proteínas Recombinantes , Escherichia coli , Imunoglobulina G , EpitoposRESUMO
Narrow odd dwarf (nod) and Liguleless narrow (Lgn) are pleiotropic maize mutants that both encode plasma membrane proteins, cause similar developmental patterning defects, and constitutively induce stress signaling pathways. To investigate how these mutants coordinate maize development and physiology, we screened for protein interactors of NOD by affinity purification. LGN was identified by this screen as a strong candidate interactor, and we confirmed the NOD-LGN molecular interaction through orthogonal experiments. We further demonstrated that LGN, a receptor-like kinase, can phosphorylate NOD in vitro, hinting that they could act in intersecting signal transduction pathways. To test this hypothesis, we generated Lgn-R;nod mutants in two backgrounds (B73 and A619), and found that these mutations enhance each other, causing more severe developmental defects than either single mutation on its own, with phenotypes including very narrow leaves, increased tillering, and failure of the main shoot. Transcriptomic and metabolomic analyses of the single and double mutants in the two genetic backgrounds revealed widespread induction of pathogen defense genes and a shift in resource allocation away from primary metabolism in favor of specialized metabolism. These effects were similar in each single mutant and heightened in the double mutant, leading us to conclude that NOD and LGN act cumulatively in overlapping signaling pathways to coordinate growth-defense tradeoffs in maize.
Assuntos
Proteínas de Plantas , Zea mays , Zea mays/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Folhas de Planta/metabolismo , Fenótipo , Mutação , Regulação da Expressão Gênica de PlantasRESUMO
Posttranslational modifications (PTMs) such as phosphorylation, acetylation, and glycosylation are an essential regulatory mechanism of protein function and interaction, and they are associated with a wide range of biological processes. Since most PTMs alter the molecular mass of a protein, mass spectrometry (MS) is the ideal analytical tool for studying various PTMs. However, PTMs are often present in substoichiometric levels, and therefore their unmodified counterpart often suppresses their signal in MS. Consequently, PTM analysis by MS is a challenging task, requiring highly specialized and sensitive PTM-specific enrichment methods. Currently, several methods have been implemented for PTM enrichment, and each of them has its drawbacks and advantages as they differ in selectivity and specificity toward specific protein modifications. Unfortunately, for the vast majority of more than 400 known modifications, we have no or poor tools for selective enrichment.Here, we describe a comprehensive workflow to simultaneously study phosphorylation, acetylation, and N-linked sialylated glycosylation from the same biological sample. The protocol involves an initial titanium dioxide (TiO2) step to enrich for phosphopeptides and sialylated N-linked glycopeptides followed by glycan release and post-fractionation using sequential elution from immobilized metal affinity chromatography (SIMAC) to separate mono-phosphorylated and deglycosylated peptides from multi-phosphorylated ones. The IMAC flow-through and acidic elution are subsequently subjected to a next round of TiO2 enrichment for further separation of mono-phosphopeptides from deglycosylated peptides. Furthermore, the lysine-acetylated peptides present in the first TiO2 flow-through fraction are enriched by immunoprecipitation (IP) after peptide cleanup. Finally, the samples are fractionated by high pH reversed phase chromatography (HpH) or hydrophilic interaction liquid chromatography (HILIC ) to reduce sample complexity and increase the coverage in the subsequent LC-MS /MS analysis. This allows the analysis of multiple types of modifications from the same highly complex biological sample without decreasing the quality of each individual PTM study.
Assuntos
Processamento de Proteína Pós-Traducional , Proteínas/análise , Proteômica , Acetilação , Cromatografia de Afinidade , Cromatografia de Fase Reversa , Glicosilação , Imunoprecipitação , Fosforilação , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Titânio/química , Fluxo de TrabalhoRESUMO
BACKGROUND: Cardiac hypertrophic growth is mediated by robust changes in gene expression and changes that underlie the increase in cardiomyocyte size. The former is regulated by RNA polymerase II (pol II) de novo recruitment or loss; the latter involves incremental increases in the transcriptional elongation activity of pol II that is preassembled at the transcription start site. The differential regulation of these distinct processes by transcription factors remains unknown. Forkhead box protein O1 (FoxO1) is an insulin-sensitive transcription factor that is also regulated by hypertrophic stimuli in the heart. However, the scope of its gene regulation remains unexplored. METHODS: To address this, we performed FoxO1 chromatin immunoprecipitation-deep sequencing in mouse hearts after 7 days of isoproterenol injections (3 mg·kg-1·mg-1), transverse aortic constriction, or vehicle injection/sham surgery. RESULTS: Our data demonstrate increases in FoxO1 chromatin binding during cardiac hypertrophic growth, which positively correlate with extent of hypertrophy. To assess the role of FoxO1 on pol II dynamics and gene expression, the FoxO1 chromatin immunoprecipitation-deep sequencing results were aligned with those of pol II chromatin immunoprecipitation-deep sequencing across the chromosomal coordinates of sham- or transverse aortic constriction-operated mouse hearts. This uncovered that FoxO1 binds to the promoters of 60% of cardiac-expressed genes at baseline and 91% after transverse aortic constriction. FoxO1 binding is increased in genes regulated by pol II de novo recruitment, loss, or pause-release. In vitro, endothelin-1- and, in vivo, pressure overload-induced cardiomyocyte hypertrophic growth is prevented with FoxO1 knockdown or deletion, which was accompanied by reductions in inducible genes, including Comtd1 in vitro and Fstl1 and Uck2 in vivo. CONCLUSIONS: Together, our data suggest that FoxO1 may mediate cardiac hypertrophic growth via regulation of pol II de novo recruitment and pause-release; the latter represents the majority (59%) of FoxO1-bound, pol II-regulated genes after pressure overload. These findings demonstrate the breadth of transcriptional regulation by FoxO1 during cardiac hypertrophy, information that is essential for its therapeutic targeting.
Assuntos
Cardiomegalia/metabolismo , Proteínas Relacionadas à Folistatina/metabolismo , Proteína Forkhead Box O1/metabolismo , Uridina Quinase/metabolismo , Animais , Cardiomegalia/genética , Proteínas Relacionadas à Folistatina/genética , Proteína Forkhead Box O1/genética , Camundongos , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Uridina Quinase/genéticaRESUMO
Aim: GDF15 levels are a biomarker for metformin use. We performed the functional annotation of noncoding genome-wide association study (GWAS) SNPs for GDF15 levels and the Genotype-Tissue Expression (GTEx)-expression quantitative trait loci (eQTLs) for GDF15 expression within metformin-activated enhancers around GDF15. Materials & methods: These enhancers were identified using chromatin immunoprecipitation followed by sequencing data for active (H3K27ac) and silenced (H3K27me3) histone marks on human hepatocytes treated with metformin, Encyclopedia of DNA Elements data and cis-regulatory elements assignment tools. Results: The GWAS lead SNP rs888663, the SNP rs62122429 associated with GDF15 levels in the Outcome Reduction with Initial Glargine Intervention trial, and the GTEx-expression quantitative trait locus rs4808791 for GDF15 expression in whole blood are located in a metformin-activated enhancer upstream of GDF15 and tightly linked in Europeans and East Asians. Conclusion: Noncoding variation within a metformin-activated enhancer may increase GDF15 expression and help to predict GDF15 levels.
Assuntos
Estudo de Associação Genômica Ampla/métodos , Fator 15 de Diferenciação de Crescimento/biossíntese , Fator 15 de Diferenciação de Crescimento/genética , Metformina/farmacologia , Polimorfismo de Nucleotídeo Único/genética , Linhagem Celular , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Hipoglicemiantes/farmacologia , Polimorfismo de Nucleotídeo Único/efeitos dos fármacosRESUMO
BACKGROUND: BMPR-1B is part of the transforming growth factor ß super family and plays a pivotal role in ewe litter size. Functional loss of exon-8 mutations in the BMPR-1B gene (namely the FecB gene) can increase both the ewe ovulation rate and litter size. RESULTS: This study constructed a eukaryotic expression system, prepared a monoclonal antibody, and characterized BMPR-1B/FecB protein-protein interactions (PPIs). Using Co-immunoprecipitation coupled to mass spectrometry (Co-IP/MS), 23 proteins were identified that specifically interact with FecB in ovary extracts of ewes. Bioinformatics analysis of selected PPIs demonstrated that FecB associated with several other BMPs, primarily via signal transduction in the ovary. FecB and its associated interaction proteins enriched the reproduction process via BMP2 and BMP4 pathways. Signal transduction was identified via Smads proteins and TGF-beta signaling pathway by analyzing the biological processes and pathways. Moreover, other target proteins (GDF5, GDF9, RhoD, and HSP 10) that interact with FecB and that are related to ovulation and litter size in ewes were identified. CONCLUSIONS: In summary, this research identified a novel pathway and insight to explore the PPi network of BMPR-1B.
Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Eucariotos/genética , Ovário/metabolismo , Mapas de Interação de Proteínas/genética , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Biologia Computacional , Eucariotos/metabolismo , Feminino , Genótipo , Espectrometria de Massas , Mutação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Ovinos , Transdução de SinaisRESUMO
Immunoprecipitation is a helpful tool to assess interactions between proteins and proteins or nucleic acids (DNA or RNA). Its principle consists in capturing and enriching one or multiple target proteins from a complex sample with a specific antibody conjugated to a solid matrix and isolating the RNA and/or protein molecules associated to those target(s) group of proteins that can be further identified by advanced techniques such as RNA-seq and/or mass spectrometry. Since this technique allows for identifying, mapping, and checking new protein-protein and protein-RNA interactions, its use is very convenient in situations where many proteins remain with their functions uncharacterized, as is the case of the protozoan Trypanosoma cruzi. Here we describe a protocol that is based on the cryogrinding method for cell lysis and the use of antibodies conjugated to magnetic beads to capture and purify protein complexes in a robust and efficient way.
Assuntos
Separação Imunomagnética/métodos , Imunoprecipitação/métodos , Substâncias Macromoleculares/isolamento & purificação , Trypanosoma cruzi/fisiologia , Substâncias Macromoleculares/metabolismo , Espectrometria de Massas/métodos , Parasitologia/métodos , Mapeamento de Interação de Proteínas , Proteínas de Protozoários/isolamento & purificação , Proteínas de Protozoários/metabolismo , RNA de Protozoário/isolamento & purificação , RNA de Protozoário/metabolismoRESUMO
BACKGROUND: BMPR-1B is part of the transforming growth factor ß super family and plays a pivotal role in ewe litter size. Functional loss of exon-8 mutations in the BMPR-1B gene (namely the FecB gene) can increase both the ewe ovulation rate and litter size. RESULTS: This study constructed a eukaryotic expression system, prepared a monoclonal antibody, and characterized BMPR-1B/FecB protein-protein interactions (PPIs). Using Co-immunoprecipitation coupled to mass spectrometry (Co-IP/MS), 23 proteins were identified that specifically interact with FecB in ovary extracts of ewes. Bioinformatics analysis of selected PPIs demonstrated that FecB associated with several other BMPs, primarily via signal transduction in the ovary. FecB and its associated interaction proteins enriched the reproduction process via BMP2 and BMP4 pathways. Signal transduction was identified via Smads proteins and TGF-beta signaling pathway by analyzing the biological processes and pathways. Moreover, other target proteins (GDF5, GDF9, RhoD, and HSP 10) that interact with FecB and that are related to ovulation and litter size in ewes were identified. CONCLUSIONS: In summary, this research identified a novel pathway and insight to explore the PPi network of BMPR-1B.
Assuntos
Animais , Feminino , Ovário/metabolismo , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Eucariotos/genética , Mapas de Interação de Proteínas/genética , Espectrometria de Massas , Polimorfismo de Fragmento de Restrição , Ovinos , Transdução de Sinais , Reação em Cadeia da Polimerase , Biologia Computacional , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Eucariotos/metabolismo , Genótipo , MutaçãoRESUMO
Competing endogenous RNAs (ceRNAs) are natural transcripts that can act as endogenous sponges of microRNAs (miRNAs), modulating miRNA action upon target mRNAs. Circular RNAs (circRNAs) are one among the various classes of ceRNAs. They are produced from a process called back-splicing and have been identified in many eukaryotes. In plants, their effective action as a miRNA sponge was not yet demonstrated. To address this question, public mRNAseq data from Argonaute-immunoprecipitation libraries (AGO-IP) of Arabidopsis thaliana flowers were used in association with a bioinformatics comparative multi-method to identify putative circular RNAs. A total of 27,812 circRNAs, with at least two reads at the back-splicing junction, were identified. Further analyses were used to select those circRNAs with potential miRNAs binding sites. As AGO forms a ternary complex with miRNA and target mRNA, targets count in AGO-IP and input libraries were compared, demonstrating that mRNA targets of these miRNAs are enriched in AGO-IP libraries. Through this work, five circRNAs that may function as miRNA sponges were identified and one of them were validated by PCR and sequencing. Our findings indicate that this post-transcriptional regulation can also occur in plants.
RESUMO
Trypanosoma cruzi, the etiological agent of Chagas disease, has been widely studied, reflecting both its medical importance and the particular features that make this pathogen an attractive model for basic biological studies. The repression of transcripts by messenger ribonucleoprotein (mRNP) complexes is an important pathway of post-transcriptional regulation in eukaryotes, including T. cruzi. RBSR1 is a serine-arginine (SR)-rich RNA-binding protein (RBP) in T. cruzi that contains one RNA-recognition motif (RRM); this protein has a primarily nuclear localization and is developmentally regulated, not being detected in metacyclic trypomastigotes. RBSR1 interacts with other RBPs, such as UBP1 and UBP2, and the nuclear SR-protein TRRM1. Phylogenetic analysis indicated that RBSR1 is orthologous to the human splicing factor SRSF7, what might indicate its possible involvement in pre-RNA processing. Accordingly, ribonomics data showed the enrichment of snoRNAs and snRNAs in the RBSR1 immunoprecipiatation complex, hence reinforcing the supposition that this protein might be involved in RNA processing in the nucleus.
Assuntos
Proteínas de Protozoários/genética , Proteínas de Ligação a RNA/genética , Trypanosoma cruzi/genética , Sequência de Aminoácidos , Filogenia , Proteínas de Protozoários/metabolismo , Proteínas de Ligação a RNA/metabolismo , Trypanosoma cruzi/metabolismoRESUMO
This chapter describes the propagation and characterization of transplantable insulinoma cells as model of insulin-producing pancreatic islet cells in the rat. Here, the cells are propagated by transplantation into rats followed by harvesting after growth for approximately 1 month. The cells are then purified by Percoll density gradient centrifugation and characterized by pulse-chase radiolabelling and immunoprecipitation of the insulin-related peptides. The results show that the transplantable insulinoma cells produce insulin in a manner similar to that found in normal pancreatic islets.
Assuntos
Técnicas de Cultura de Células/métodos , Imunoprecipitação/métodos , Insulinoma/patologia , Neoplasias Pancreáticas/genética , Animais , Proliferação de Células/genética , Humanos , Insulina/genética , Secreção de Insulina/genética , Insulinoma/genética , Ilhotas Pancreáticas/crescimento & desenvolvimento , Ilhotas Pancreáticas/patologia , Neoplasias Pancreáticas/patologia , RatosRESUMO
Epigenetic regulation is achieved at many levels by different factors such as tissue-specific transcription factors, members of the basal transcriptional apparatus, chromatin-binding proteins, and noncoding RNAs. Importantly, chromatin structure dictates the availability of a specific genomic locus for transcriptional activation as well as the efficiency with which transcription can occur. Chromatin immunoprecipitation (ChIP) is a method that allows elucidating gene regulation at the molecular level by assessing if chromatin modifications or proteins are present at a specific locus. Initially, the majority of ChIP experiments were performed on cultured cell lines and more recently this technique has been adapted to a variety of tissues in different model organisms. Using ChIP on mouse embryos, it is possible to document the presence or absence of specific proteins and chromatin modifications at genomic loci in vivo during mammalian development and to get biological meaning from observations made on tissue culture analyses. We describe here a ChIP protocol on freshly isolated mouse embryonic somites for in vivo analysis of muscle specific transcription factor binding on chromatin. This protocol has been easily adapted to other mouse embryonic tissues and has also been successfully scaled up to perform ChIP-Seq.
Assuntos
Imunoprecipitação da Cromatina/métodos , Embrião de Mamíferos/metabolismo , Animais , Epigênese Genética/genética , Feminino , Camundongos , Desenvolvimento Muscular/genética , Desenvolvimento Muscular/fisiologia , Proteína MyoD/genética , Miogenina/genética , GravidezRESUMO
Pulse-chase radiolabeling of cells with radioactive amino acids is a common method for studying the biosynthesis of proteins. The labeled proteins can then be immunoprecipitated and analyzed by electrophoresis and gel imaging techniques. This chapter presents a protocol for the biosynthetic labeling and immunoprecipitation of pancreatic islet proteins which are known to be affected in disorders such as diabetes, obesity, and metabolic syndrome.
Assuntos
Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Marcação por Isótopo , Animais , Biomarcadores , Eletroforese , Imunoprecipitação , Técnicas de Imunoadsorção , Insulina/metabolismo , Marcação por Isótopo/métodos , Ratos , Radioisótopos de Enxofre/metabolismoRESUMO
In order to comprehend the function of a particular protein, identification of the interacting protein partners is a useful approach. Co-immunoprecipitation (Co-IP) is employed to test physical interactions between proteins. Specific antibodies or antibodies against tagged versions can be used to immunoprecipitate the proteins. In this chapter, we describe a method to carry out Co-IP using recombinant membrane proteins expressed in yeast microsomal fractions.
Assuntos
Anticorpos/química , Imunoprecipitação/métodos , Mapeamento de Interação de Proteínas/métodos , Proteína Quinase C/isolamento & purificação , Solanum lycopersicum/genética , Western Blotting , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Isoenzimas/genética , Isoenzimas/isolamento & purificação , Isoenzimas/metabolismo , Ligantes , Solanum lycopersicum/enzimologia , Microssomos/química , Ligação Proteica , Proteína Quinase C/genética , Proteína Quinase C/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMO
INTRODUCTION: Dengue is a disease caused by one of four serotypes of the dengue virus (DENV) and is endemic in approximately 130 countries. The incidence of dengue has increased dramatically in recent decades, as well as the frequency and magnitude of outbreaks. Despite all efforts, there are no prophylactic or therapeutic treatments for the disease. Accordingly, research on the processes governing the DENV infection cycle is essential to develop vaccines or antiviral therapies. One of themost attractive DENV molecules to investigate is nonstructural protein 3 (NS3), which is essential for viral replication and a major immune target for infection. OBJECTIVE: To produce antibodies to support future studies on NS3 and its cellular interactions with other proteins. MATERIALS AND METHODS: Two recombinant proteins of the helicase domain of DENV NS3 serotype 2 were expressed, and used to immunize mice and produce polyclonal antibodies. RESULTS: The antibodies produced were useful in Western blot and immunofluorescence tests. We report an NS3 antibody that immunoprecipitates the viral protein and detects it in Western blot with no need to over-express it or use cell extracts with metabolic radiolabeling. CONCLUSION: The recombinant proteins expressed and the antibodies produced constitute valuable tools for studying DENV infectious processes involving NS3 and for evaluating tests designed to interfere with its functions.
Assuntos
Anticorpos Antivirais/imunologia , Vírus da Dengue/imunologia , Dengue/virologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/fisiologia , Animais , Anticorpos Antivirais/química , Anticorpos Antivirais/metabolismo , Western Blotting , Humanos , Camundongos , RNA Helicases/química , RNA Helicases/genética , RNA Helicases/metabolismo , Serina Endopeptidases/química , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Proteínas não Estruturais Virais/química , Replicação Viral/genética , Replicação Viral/imunologiaRESUMO
Pulse radiolabelling of cells with radioactive amino acids is a common method for studying the biosynthesis of proteins. The labelled proteins can then be immunoprecipitated and analysed by electrophoresis and imaging techniques. This chapter presents a protocol for the biosynthetic labelling and immunoprecipitation of pancreatic islet proteins which are known to be affected in psychiatric disorders such as schizophrenia.
Assuntos
Imunoprecipitação/métodos , Insulina/análise , Ilhotas Pancreáticas/química , Pró-Proteína Convertase 2/análise , Vesículas Secretórias/química , Especificidade de Anticorpos , Cromatografia em Agarose/métodos , Eletroforese/métodos , Glucose/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Imunoprecipitação/instrumentação , Imunoadsorventes , Insulina/biossíntese , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Marcação por Isótopo/métodos , Metionina/análise , Pró-Proteína Convertase 2/biossíntese , Vesículas Secretórias/enzimologia , Radioisótopos de Enxofre/análise , UreiaRESUMO
A single protein is often capable of binding with many partners, enabling potential effects on either protein, such as modifying its expression or activity. However, due to the complex nature of in vivo systems, it is often difficult to perform nontargeted assays with a protein of interest. Methods in discovery proteomics must be used to find potential interactors to pave the way for additional, more focused studies. This protocol describes the biological steps needed to create an interactome focused on a single protein target through co-immunoprecipitation.
Assuntos
Imunoprecipitação/métodos , Mapeamento de Interação de Proteínas/métodos , Fracionamento Celular/métodos , Cromatografia de Afinidade/métodos , Cromatografia Líquida/métodos , Humanos , Indicadores e Reagentes , Ligação Proteica , Proteômica/métodos , Espectrometria de Massas em Tandem/métodosRESUMO
Resumen Introducción: El dengue es una enfermedad causada por uno de los cuatro serotipos del virus del dengue (DENV) y es endémica en, aproximadamente, 130 países. Su incidencia ha aumentado notablemente en las últimas décadas, así como la frecuencia y la magnitud de los brotes. A pesar de los esfuerzos, no existen tratamientos profilácticos ni terapéuticos contra la enfermedad y, en ese contexto, el estudio de los procesos que gobiernan el ciclo de infección del DENV es esencial para desarrollar vacunas o terapias antivirales. Una de las moléculas del DENV más prometedoras es la proteína no estructural 3 (NS3), la cual es indispensable para la replicación viral y es uno de los principales blancos inmunológicos durante la infección. Objetivo: Producir anticuerpos policlonales para contribuir a los futuros estudios sobre las interacciones entre la proteína NS3 y otras proteínas celulares. Materiales y métodos: Se expresaron dos proteínas recombinantes del dominio helicasa de NS3 del DENV de serotipo 2, las cuales se emplearon para inmunizar ratas y producir anticuerpos policlonales. Resultados: Los anticuerpos producidos fueron útiles en ensayos de Western blot e inmunofluorescencia y se reportó por primera vez un anticuerpo policlonal anti-NS3 que permitió la inmunoprecipitación de la proteína viral y la detecta con Western blot sin necesidad de inducir sobreexpresión de NS3 o de usar extractos de células marcados metabólicamente con radioisótopos. Conclusión: Las proteínas recombinantes expresadas y los anticuerpos producidos constituyen herramientas valiosas para estudiar procesos infecciosos del DENV que involucren a la proteína NS3 y evaluar pruebas dirigidas a interferir las funciones de esta proteína.
Abstract Introduction: Dengue is a disease caused by one of four serotypes of the dengue virus (DENV) and is endemic in approximately 130 countries. The incidence of dengue has increased dramatically in recent decades, as well as the frequency and magnitude of outbreaks. Despite all efforts, there are no prophylactic or therapeutic treatments for the disease. Accordingly, research on the processes governing the DENV infection cycle is essential to develop vaccines or antiviral therapies. One of the most attractive DENV molecules to investigate is nonstructural protein 3 (NS3), which is essential for viral replication and a major immune target for infection. Objective: To produce antibodies to support future studies on NS3 and its cellular interactions with other proteins. Materials and methods: Two recombinant proteins of the helicase domain of DENV NS3 serotype 2 were expressed, and used to immunize mice and produce polyclonal antibodies. Results: The antibodies produced were useful in Western blot and immunofluorescence tests. We report an NS3 antibody that immunoprecipitates the viral protein and detects it in Western blot with no need to over-express it or use cell extracts with metabolic radiolabeling.