Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 7.850
Filtrar
1.
Int J Mol Sci ; 25(7)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38612545

RESUMO

HIV-1 capsid protein (CA) is the molecular target of the recently FDA-approved long acting injectable (LAI) drug lenacapavir (GS-6207). The quick emergence of CA mutations resistant to GS-6207 necessitates the design and synthesis of novel sub-chemotypes. We have conducted the structure-based design of two new sub-chemotypes combining the scaffold of GS-6207 and the N-terminal cap of PF74 analogs, the other important CA-targeting chemotype. The design was validated via induced-fit molecular docking. More importantly, we have worked out a general synthetic route to allow the modular synthesis of novel GS-6207 subtypes. Significantly, the desired stereochemistry of the skeleton C2 was confirmed via an X-ray crystal structure of the key synthetic intermediate 22a. Although the newly synthesized analogs did not show significant potency, our efforts herein will facilitate the future design and synthesis of novel subtypes with improved potency.


Assuntos
Fármacos Anti-HIV , HIV-1 , Proteínas do Capsídeo/genética , HIV-1/genética , Simulação de Acoplamento Molecular , Fármacos Anti-HIV/farmacologia , Mutação
2.
Biochem Biophys Res Commun ; 710: 149878, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38608492

RESUMO

Sapovirus (SaV) is a nonenveloped RNA virus that causes acute gastroenteritis in humans. Although SaV is a clinically important pathogen in children, an effective vaccine is currently unavailable. The capsid protein VP1 of SaVs forms the outer shell of the virion and is highly diverse, as often seen in the virion-surface proteins of RNA viruses, creating an obstacle for vaccine development. We here report a unique phenomenon pertaining to the variation of SaV VP1. Phylogenetic and information entropy analyses using full-length VP1 sequences from a public database consistently showed that the amino acid sequences of the VP1 protein have been highly conserved over more than 40 years in the major epidemic genotype GI.1 but not in GI.2. Structural modeling showed that even the VP1 P2 subdomain, which is arranged on the outermost shell of the virion and presumably exposed to anti-SaV antibodies, remained highly homogeneous in GI.1 but not in GI.2. These results suggest strong evolutionary constraints against amino acid changes in the P2 subdomain of the SaV GI.1 capsid and illustrate a hitherto unappreciated mechanism, i.e., preservation of the VP1 P2 subdomain, involved in SaV survival. Our findings could have important implications for the development of an anti-SaV vaccine.


Assuntos
Sapovirus , Vacinas , Criança , Humanos , Sapovirus/genética , Proteínas do Capsídeo/genética , Filogenia , Aminoácidos/genética , Genótipo , Fezes
3.
Arch Virol ; 169(5): 105, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38637359

RESUMO

In this study, we identified a novel double-strand RNA (dsRNA) mycovirus in Pyricularia oryzae, designated "Magnaporthe oryzae partitivirus 4" (MoPV4). The genome of MoPV4 consists of a dsRNA-1 segment encoding an RNA-dependent RNA polymerase (RdRP) and a dsRNA-2 segment encoding a capsid protein (CP). Phylogenetic analysis indicated that MoPV4 belongs to the genus Gammapartitivirus within family Partitiviridae. The particles of MoPV4 are isometric with a diameter of about 32.4 nm. Three-dimensional structure predictions indicated that the RdRP of MoPV4 forms a classical right-handed conformation, while the CP has a reclining-V shape.


Assuntos
Ascomicetos , Micovírus , Vírus de RNA , RNA Viral/genética , Filogenia , Vírus de RNA/genética , Proteínas do Capsídeo/genética , RNA Polimerase Dependente de RNA/genética , Genoma Viral , Micovírus/genética , RNA de Cadeia Dupla/genética , Fases de Leitura Aberta
4.
Virol J ; 21(1): 87, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38641833

RESUMO

BACKGROUND: Bovine parvovirus (BPV) is an autonomous DNA virus with a smaller molecular size and subtle differences in its structural proteins, unlike other animal parvoviruses. More importantly, this virus has the potential to produce visible to silent economic catastrophes in the livestock business, despite receiving very little attention. Parvoviral virus-like particles (VLPs) as vaccines and as logistical platforms for vaccine deployment are well studied. However, no single experimental report on the role of VP1 in the assembly and stability of BPV-VLPs is available. Furthermore, the self-assembly, integrity and stability of the VLPs of recombinant BPV VP2 in comparison to VP1 VP2 Cap proteins using any expression method has not been studied previously. In this study, we experimentally evaluated the self-assembling ability with which BPV virus-like particles (VLPs) could be synthesized from a single structural protein (VP2) and by integrating both VP2 and VP1 amino acid sequences. METHODS: In silico and experimental cloning methods were carried out. His-tagged and without-His-tag VP2 and V1VP2-encoding amino acid sequences were cloned and inserted into pFastbacdual, and insect cell-generated recombinant protein was evaluated by SDS‒PAGE and western blot. Period of infectivity and expression level were determined by IFA. The integrity and stability of the BPV VLPs were evaluated by transmission electron microscopy. The secondary structure of the BPV VLPs from both VP2 and V1VP2 was analyzed by circular dichroism. RESULTS: Our findings show that VP2 alone was equally expressed and purified into detectable proteins, and the stability at different temperatures and pH values was not appreciably different between the two kinds of VLPs. Furthermore, BPV-VP2 VLPs were praised for their greater purity and integrity than BPV-VP1VP2 VLPs, as indicated by SDS‒PAGE. Therefore, our research demonstrates that the function of VP1 has no bearing on the stability or integrity of BPV-VLPs. CONCLUSIONS: In summary, incredible physiochemically stable BPV VP2-derived VLPs have been found to be promising candidates for the development of multivalent vaccines and immunodiagnostic kits against enteric viruses and to carry heterogeneous epitopes for various economically important livestock diseases.


Assuntos
Bocavirus , Parvovirus , Vacinas , Animais , Baculoviridae/genética , Proteínas Recombinantes/genética , Proteínas do Capsídeo/genética
5.
Int J Mol Sci ; 25(7)2024 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-38612429

RESUMO

Norovirus (NoV) genogroup II, polymerase type P31, capsid genotype 4, Sydney_2012 variant (GII.P31/GII.4_Sydney_2012) has been circulating at high levels for over a decade, raising the question of whether this strain is undergoing molecular alterations without demonstrating a substantial phylogenetic difference. Here, we applied next-generation sequencing to learn more about the genetic diversity of 14 GII.P31/GII.4_Sydney_2012 strains that caused epidemics in a specific region of Japan, with 12 from Kyoto and 2 from Shizuoka, between 2012 and 2022, with an emphasis on amino acid (aa) differences in all three ORFs. We found numerous notable aa alterations in antigenic locations in the capsid region (ORF2) as well as in other ORFs. In all three ORFs, earlier strains (2013-2016) remained phylogenetically distinct from later strains (2019-2022). This research is expected to shed light on the evolutionary properties of dominating GII.P31/GII.4_Sydney_2012 strains, which could provide useful information for viral diarrhea prevention and treatment.


Assuntos
Evolução Molecular , Norovirus , Japão/epidemiologia , Filogenia , Evolução Biológica , Proteínas do Capsídeo/genética , Norovirus/genética
6.
Viruses ; 16(3)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38543807

RESUMO

Today, adeno-associated virus (AAV)-based vectors are arguably the most promising in vivo gene delivery vehicles for durable therapeutic gene expression. Advances in molecular engineering, high-throughput screening platforms, and computational techniques have resulted in a toolbox of capsid variants with enhanced performance over parental serotypes. Despite their considerable promise and emerging clinical success, there are still obstacles hindering their broader use, including limited transduction capabilities, tissue/cell type-specific tropism and penetration into tissues through anatomical barriers, off-target tissue biodistribution, intracellular degradation, immune recognition, and a lack of translatability from preclinical models to clinical settings. Here, we first describe the transduction mechanisms of natural AAV serotypes and explore the current understanding of the systemic and cellular hurdles to efficient transduction. We then outline progress in developing designer AAV capsid variants, highlighting the seminal discoveries of variants which can transduce the central nervous system upon systemic administration, and, to a lesser extent, discuss the targeting of the peripheral nervous system, eye, ear, lung, liver, heart, and skeletal muscle, emphasizing their tissue and cell specificity and translational promise. In particular, we dive deeper into the molecular mechanisms behind their enhanced properties, with a focus on their engagement with host cell receptors previously inaccessible to natural AAV serotypes. Finally, we summarize the main findings of our review and discuss future directions.


Assuntos
Capsídeo , Dependovirus , Capsídeo/metabolismo , Dependovirus/metabolismo , Sorogrupo , Distribuição Tecidual , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Tropismo , Vetores Genéticos/genética
7.
J Virol ; 98(4): e0030824, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38497663

RESUMO

Host antiviral proteins inhibit primate lentiviruses and other retroviruses by targeting many features of the viral life cycle. The lentiviral capsid protein and the assembled viral core are known to be inhibited through multiple, directly acting antiviral proteins. Several phenotypes, including those known as Lv1 through Lv5, have been described as cell type-specific blocks to infection against some but not all primate lentiviruses. Here we review important features of known capsid-targeting blocks to infection together with several blocks to infection for which the genes responsible for the inhibition still remain to be identified. We outline the features of these blocks as well as how current methodologies are now well suited to find these antiviral genes and solve these long-standing mysteries in the HIV and retrovirology fields.


Assuntos
HIV-1 , Lentivirus , Animais , Lentivirus/genética , Lentivirus/metabolismo , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Capsídeo/metabolismo , HIV-1/fisiologia , Antivirais/metabolismo
8.
Vaccine ; 42(11): 2848-2857, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38514351

RESUMO

Porcine circovirus type 2 (PCV2) is an important pathogen harmful to global pig production, which causes immunosuppression and serious economic losses. PCV2 capsid (Cap) protein expressed by E. coli or baculovirus-insect cells are often used in preparation of PCV2 subunit vaccines, but the latter is expensive to produce. It is therefore crucial to comparison of the immune effects of Cap protein expressed by the above two expression systems for reducing the production cost and guaranteeing PCV2 vaccine quality. In this study, the PCV2d-Cap protein lacking nuclear localization signal (NLS), designated as E. coli-Cap and Bac-Cap, was expressed by E. coli and baculovirus-Spodoptera frugiperda Sf9 (Bac-Sf9) cells, respectively. The expressed Cap proteins could self-assemble into virus-like particles (VLPs), but the Bac-Cap-assembled VLPs were more regular. The two system-expressed Cap proteins induced similar specific IgG responses in mice, but the neutralizing antibody levels of Bac-Cap-immunized mice was higher than those of E. coli-Cap. After PCV2 challenge, IL-10 in Bac-Cap immunized mice decreased significantly than that in E. coli-Cap. The lesions and PCV2 antigen positive cells in tissues of mice immunized with E. coli-Cap and Bac-Cap were significantly reduced, and Bac-Cap appeared mild lesions and fewer PCV2 antigen-positive cells compared with E. coli-Cap immunized mice. The study indicated that Cap proteins expressed by E. coli and Bac-Sf9 cells could induce specific protective immunity, but the latter induced more effective immunity, which provides valuable information for the research and development of PCV2 vaccine.


Assuntos
Infecções por Circoviridae , Circovirus , Vacinas de Partículas Semelhantes a Vírus , Vacinas Virais , Animais , Suínos , Camundongos , Proteínas do Capsídeo/genética , Anticorpos Antivirais , Circovirus/genética , Escherichia coli/metabolismo , Baculoviridae/genética , Infecções por Circoviridae/prevenção & controle , Infecções por Circoviridae/veterinária
9.
Int J Biol Macromol ; 265(Pt 1): 130847, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38490381

RESUMO

Getah virus (GETV) belongs to the Alphavirus genus in the Togaviridae family and is a zoonotic arbovirus causing disease in both humans and animals. The capsid protein (CP) of GETV regulates the viral core assembly, but the mechanism underlying this process is poorly understood. In this study, we demonstrate that CP undergoes liquid-liquid phase separation (LLPS) with the GETV genome RNA (gRNA) in vitro and forms cytoplasmic puncta in cells. Two regions of GETV gRNA (nucleotides 1-4000 and 5000-8000) enhance CP droplet formation in vitro and the lysine-rich Link region of CP is essential for its phase separation. CP(K/R) mutant with all lysines in the Link region replaced by arginines exhibits improved LLPS versus wild type (WT) CP, but CP(K/E) mutant with lysines substituted by glutamic acids virtually loses condensation ability. Consistently, recombinant virus mutant with CP(K/R) possesses significantly higher gRNA binding affinity, virion assembly efficiency and infectivity than the virus with WT-CP. Overall, our findings provide new insights into the understanding of GETV assembly and development of new antiviral drugs against alphaviruses.


Assuntos
Alphavirus , Animais , Humanos , Alphavirus/genética , Alphavirus/metabolismo , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , RNA Viral/genética , RNA Guia de Sistemas CRISPR-Cas , Genômica , Vírion/genética
10.
Environ Sci Technol ; 58(12): 5279-5289, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38488515

RESUMO

The sensitivity of enteroviruses to disinfectants varies among genetically similar variants and coincides with amino acid changes in capsid proteins, although the effect of individual substitutions remains unknown. Here, we employed reverse genetics to investigate how amino acid substitutions in coxsackievirus B5 (CVB5) capsid proteins affect the virus' sensitivity to free chlorine and heat treatment. Of ten amino acid changes observed in CVB5 variants with free chlorine resistance, none significantly reduced the chlorine sensitivity, indicating a minor role of the capsid composition in chlorine sensitivity of CVB5. Conversely, a subset of these amino acid changes located at the C-terminal region of viral protein 1 led to reduced heat sensitivity. Cryo-electron microscopy revealed that these changes affect the assembly of intermediate viral states (altered and empty particles), suggesting that the mechanism for reduced heat sensitivity could be related to improved molecular packing of CVB5, resulting in greater stability or altered dynamics of virus uncoating during infection.


Assuntos
Proteínas do Capsídeo , Cloro , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/química , Cloro/farmacologia , Microscopia Crioeletrônica , Substituição de Aminoácidos , Enterovirus Humano B/genética , Aminoácidos
11.
PLoS Pathog ; 20(3): e1011830, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38512975

RESUMO

Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced GTPase that inhibits human immunodeficiency virus-1 (HIV-1) infection by preventing nuclear import of the viral preintegration complex. The HIV-1 capsid (CA) is the major viral determinant for sensitivity to MX2, and complex interactions between MX2, CA, nucleoporins (Nups), cyclophilin A (CypA), and other cellular proteins influence the outcome of viral infection. To explore the interactions between MX2, the viral CA, and CypA, we utilized a CRISPR-Cas9/AAV approach to generate CypA knock-out cell lines as well as cells that express CypA from its endogenous locus, but with specific point mutations that would abrogate CA binding but should not affect enzymatic activity or cellular function. We found that infection of CypA knock-out and point mutant cell lines with wild-type HIV-1 and CA mutants recapitulated the phenotypes observed upon cyclosporine A (CsA) addition, indicating that effects of CsA treatment are the direct result of blocking CA-CypA interactions and are therefore independent from potential interactions between CypA and MX2 or other cellular proteins. Notably, abrogation of GTP hydrolysis by MX2 conferred enhanced antiviral activity when CA-CypA interactions were abolished, and this effect was not mediated by the CA-binding residues in the GTPase domain, or by phosphorylation of MX2 at position T151. We additionally found that elimination of GTPase activity also altered the Nup requirements for MX2 activity. Our data demonstrate that the antiviral activity of MX2 is affected by CypA-CA interactions in a virus-specific and GTPase activity-dependent manner. These findings further highlight the importance of the GTPase domain of MX2 in regulation of substrate specificity and interaction with nucleocytoplasmic trafficking pathways.


Assuntos
Capsídeo , Complexo de Proteínas Formadoras de Poros Nucleares , Humanos , Capsídeo/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Ciclofilina A/genética , Ciclofilina A/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Antivirais/metabolismo , Proteínas de Resistência a Myxovirus/genética , Proteínas de Resistência a Myxovirus/metabolismo
12.
Mol Biol Evol ; 41(4)2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38507667

RESUMO

Selfish genetic elements comprise significant fractions of mammalian genomes. In rare instances, host genomes domesticate segments of these elements for function. Using a complete human genome assembly and 25 additional vertebrate genomes, we re-analyzed the evolutionary trajectories and functional potential of capsid (CA) genes domesticated from Metaviridae, a lineage of retrovirus-like retrotransposons. Our study expands on previous analyses to unearth several new insights about the evolutionary histories of these ancient genes. We find that at least five independent domestication events occurred from diverse Metaviridae, giving rise to three universally retained single-copy genes evolving under purifying selection and two gene families unique to placental mammals, with multiple members showing evidence of rapid evolution. In the SIRH/RTL family, we find diverse amino-terminal domains, widespread loss of protein-coding capacity in RTL10 despite its retention in several mammalian lineages, and differential utilization of an ancient programmed ribosomal frameshift in RTL3 between the domesticated CA and protease domains. Our analyses also reveal that most members of the PNMA family in mammalian genomes encode a conserved putative amino-terminal RNA-binding domain (RBD) both adjoining and independent from domesticated CA domains. Our analyses lead to a significant correction of previous annotations of the essential CCDC8 gene. We show that this putative RBD is also present in several extant Metaviridae, revealing a novel protein domain configuration in retrotransposons. Collectively, our study reveals the divergent outcomes of multiple domestication events from diverse Metaviridae in the common ancestor of placental mammals.


Assuntos
Capsídeo , Retroelementos , Gravidez , Animais , Feminino , Humanos , Evolução Molecular , Placenta , Mamíferos/genética , Proteínas do Capsídeo/genética , Eutérios/genética , Filogenia
13.
Int J Mol Sci ; 25(5)2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38474031

RESUMO

Gene therapy holds great promise for the treatment of severe diseases, and adeno-associated virus (AAV) vectors have emerged as valuable tools in this field. However, challenges such as immunogenicity and high production costs complicate the commercial viability of AAV-based therapies. To overcome these barriers, improvements in production yield, driven through the availability of robust and sensitive characterization techniques that allow for the monitoring of critical quality attributes to deepen product and process understanding are crucial. Among the main attributes affecting viral production and performance, the ratio between empty and full capsids along with capsid protein stoichiometry are emerging as potential parameters affecting product quality and safety. This study focused on the production of AAV vectors using the baculovirus expression vector system (BEVS) in Sf9 cells and the complete characterization of AAV5 variants using novel liquid chromatography and mass spectrometry techniques (LC-MS) that, up to this point, had only been applied to reference commercially produced virions. When comparing virions produced using ATG, CTG or ACG start codons of the cap gene, we determined that although ACG was the most productive in terms of virus yield, it was also the least effective in transducing mammalian cells. This correlated with a low VP1/VP2 ratio and a higher percentage of empty capsids. Overall, this study provides insights into the impact of translational start codon modifications during rAAV5 production using the BEVS, the associated relationship with capsid packaging, capsid protein stoichiometry and potency. The developed characterization workflow using LC-MS offers a comprehensive and transferable analysis of AAV-based gene therapies, with the potential to aid in process optimization and facilitate the large-scale commercial manufacturing of these promising treatments.


Assuntos
Proteínas do Capsídeo , Dependovirus , Animais , Proteínas do Capsídeo/genética , Dependovirus/genética , Cromatografia Líquida , 60705 , Fluxo de Trabalho , Vetores Genéticos , Espectrometria de Massas em Tandem , Baculoviridae/genética , Mamíferos/metabolismo
14.
Biotechnol J ; 19(3): e2300667, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38479987

RESUMO

The recombinant adeno-associated virus (rAAV) vectors used in gene therapy are usually produced by transfecting three different plasmids (Adenoviral helper plasmid (pHelper), AAV rep/cap plasmids (pRepCap), and Transgene plasmid (pAAV-GOI)) into human embryonic kidney 293 (HEK293) cells. However, the high proportion of unwanted empty capsids generated during rAAV production is problematic. To simultaneously enhance the genome titer and full capsid ratio, the ratio of the three plasmids transfected into HEK293 cells was optimized using design-of-experiment (DoE). AAV2 and AAV9, which have different production kinetics, were selected as cell-associated and secreted model AAVs, respectively. In 125 mL Erlenmeyer flasks, the genome titers of rAAV2 and rAAV9 at DoE-optimized plasmid weight ratios (pHelper:pRep2Cap2:pAAV-GOI = 1:3.52:0.50 for rAAV2 and pHelper:pRep2Cap9:pAAV-GOI = 1:1.44:0.27 for rAAV9) were 2.23-fold and 2.26-fold higher than those in the widely used plasmid weight ratio (1:1:1), respectively. In addition, compared with the plasmid ratio of 1:1:1, the relative VP3 band intensities of rAAV2 and rAAV9, which represent the relative empty capsid ratios, were reduced by 26% and 25%, respectively, at the DoE-optimized plasmid ratio. Reduced empty capsid ratios in the DoE-optimized plasmid ratios were also confirmed using transmission electron microscopy (TEM). Taken together, regardless of the AAV serotype, DoE-aided optimization of the triple plasmid ratio was found to be an efficient means of improving the production of rAAV with a high full capsid ratio.


Assuntos
Capsídeo , Parvovirinae , Humanos , Células HEK293 , Vetores Genéticos/genética , Dependovirus/genética , Plasmídeos/genética , Proteínas do Capsídeo/genética , Parvovirinae/genética
15.
Biotechnol J ; 19(3): e2400051, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38479988

RESUMO

Recombinant adeno-associated virus (rAAV) is widely used as an in vivo delivery vector for gene therapy. It is used in a very large dose, and the large quantities required for broad applications present manufacturing challenges. We have developed a synthetic biology platform of constructing cell lines integrated with essential viral genes which can be induced to produce rAAV without plasmid transfection or virus transduction. Through iterative design-construct-characterization cycles, we have showcased the potential of this synthetic cell production system. Systems characterization of the dynamics of viral transcripts and proteins as well as virus assembly and packaging revealed that the expression level and balance of viral genome and capsid protein are keys to not only the productivity but also the full particle content, an important product quality attribute. Boosting cap gene expression by sequential transfection and integration of multiple copies of the cap gene elevated the rAAV titer to levels on a par with traditional plasmid transfection and virus infection. However, overexpression of the cap gene shifted the balance and kinetics of the genome and capsid. We independently tuned the dynamics of genome amplification and capsid protein synthesis by modulating the induction concentration as well as the time profile, and significantly enhanced full particle content while maintaining a high productivity. This strategy of constructing an inducible stable producer cell line is readily adaptable to rAAV vectors of different serotypes and payloads. It can greatly facilitate scalable production of gene therapy vectors.


Assuntos
Células Artificiais , Dependovirus , Dependovirus/genética , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Vetores Genéticos/genética , Capsídeo , Linhagem Celular
16.
Elife ; 122024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38536879

RESUMO

Recombinant adeno-associated viruses (rAAVs) are the predominant gene therapy vector. Several rAAV vectored therapies have achieved regulatory approval, but production of sufficient rAAV quantities remains difficult. The AAV Rep proteins, which are essential for genome replication and packaging, represent a promising engineering target for improvement of rAAV production but remain underexplored. To gain a comprehensive understanding of the Rep proteins and their mutational landscape, we assayed the effects of all 39,297 possible single-codon mutations to the AAV2 rep gene on AAV2 production. Most beneficial variants are not observed in nature, indicating that improved production may require synthetic mutations. Additionally, the effects of AAV2 rep mutations were largely consistent across capsid serotypes, suggesting that production benefits are capsid independent. Our results provide a detailed sequence-to-function map that enhances our understanding of Rep protein function and lays the groundwork for Rep engineering and enhancement of large-scale gene therapy production.


Assuntos
Proteínas do Capsídeo , Vetores Genéticos , Vetores Genéticos/genética , Mutação , Proteínas do Capsídeo/genética , Capsídeo , Mutagênese , Dependovirus/genética
17.
Cell Rep ; 43(3): 113902, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38431840

RESUMO

Adeno-associated virus (AAV) is a member of the genus Dependoparvovirus, which infects a wide range of vertebrate species. Here, we observe that, unlike most primate AAV isolates, avian AAV is transcriptionally silenced in human cells. By swapping the VP1 N terminus from primate AAVs (e.g., AAV8) onto non-mammalian isolates (e.g., avian AAV), we identify a minimal component of the AAV capsid that controls viral transcription and unlocks robust transduction in both human cells and mouse tissue. This effect is accompanied by increased AAV genome chromatin accessibility and altered histone methylation. Proximity ligation analysis reveals that host factors are selectively recruited by the VP1 N terminus of AAV8 but not avian AAV. Notably, these include AAV essential factors implicated in the nuclear factor κB pathway, chromatin condensation, and histone methylation. We postulate that the AAV capsid has evolved mechanisms to recruit host factors to its genome, allowing transcriptional activation in a species-specific manner.


Assuntos
Capsídeo , Dependovirus , Humanos , Animais , Camundongos , Capsídeo/metabolismo , Dependovirus/metabolismo , Histonas/metabolismo , Transcrição Viral , Vetores Genéticos , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Primatas , Especificidade de Hospedeiro , Cromatina/metabolismo
18.
J Gen Virol ; 105(3)2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38441555

RESUMO

Adeno-associated viruses (AAV) are one of the world's most promising gene therapy vectors and as a result, are one of the most intensively studied viral vectors. Despite a wealth of research into these vectors, the precise characterisation of AAVs to translocate into the host cell nucleus remains unclear. Recently we identified the nuclear localization signals of an AAV porcine strain and determined its mechanism of binding to host importin proteins. To expand our understanding of diverse AAV import mechanisms we sought to determine the mechanism in which the Cap protein from a bat-infecting AAV can interact with transport receptor importins for translocation into the nucleus. Using a high-resolution crystal structure and quantitative assays, we were able to not only determine the exact region and residues of the N-terminal domain of the Cap protein which constitute the functional NLS for binding with the importin alpha two protein, but also reveal the differences in binding affinity across the importin-alpha isoforms. Collectively our results allow for a detailed molecular view of the way AAV Cap proteins interact with host proteins for localization into the cell nucleus.


Assuntos
Quirópteros , Dependovirus , Animais , Suínos , Transporte Ativo do Núcleo Celular , Dependovirus/genética , Proteínas do Capsídeo/genética , Carioferinas , Sinais de Localização Nuclear , alfa Carioferinas/genética
19.
Viruses ; 16(2)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38399966

RESUMO

Viruses frequently contain overlapping genes, which encode functionally unrelated proteins from the same DNA or RNA region but in different reading frames. Yet, overlapping genes are often overlooked during genome annotation, in particular in DNA viruses. Here we looked for the presence of overlapping genes likely to encode a functional protein in human parvovirus B19 (genus Erythroparvovirus), using an experimentally validated software, Synplot2. Synplot2 detected an open reading frame, X, conserved in all erythroparvoviruses, which overlaps the VP1 capsid gene and is under highly significant selection pressure. In a related virus, human parvovirus 4 (genus Tetraparvovirus), Synplot2 also detected an open reading frame under highly significant selection pressure, ARF1, which overlaps the VP1 gene and is conserved in all tetraparvoviruses. These findings provide compelling evidence that the X and ARF1 proteins must be expressed and functional. X and ARF1 have the exact same location (they overlap the region of the VP1 gene encoding the phospholipase A2 domain), are both in the same frame (+1) with respect to the VP1 frame, and encode proteins with similar predicted properties, including a central transmembrane region. Further studies will be needed to determine whether they have a common origin and similar function. X and ARF1 are probably translated either from a polycistronic mRNA by a non-canonical mechanism, or from an unmapped monocistronic mRNA. Finally, we also discovered proteins predicted to be expressed from a frame overlapping VP1 in other species related to parvovirus B19: porcine parvovirus 2 (Z protein) and bovine parvovirus 3 (X-like protein).


Assuntos
Parvovirus B19 Humano , Parvovirus , Humanos , Parvovirus B19 Humano/genética , Capsídeo/metabolismo , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Fases de Leitura Aberta , Parvovirus/genética , RNA Mensageiro/metabolismo
20.
Viruses ; 16(2)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38399987

RESUMO

Rotaviruses (RVs) are a major cause of diarrhea in young children worldwide. The currently available and licensed vaccines contain live attenuated RVs. Optimization of live attenuated RV vaccines or developing non-replicating RV (e.g., mRNA) vaccines is crucial for reducing the morbidity and mortality from RV infections. Herein, a nucleoside-modified mRNA vaccine encapsulated in lipid nanoparticles (LNP) and encoding the VP7 protein from the G1 type of RV was developed. The 5' untranslated region of an isolated human RV was utilized for the mRNA vaccine. After undergoing quality inspection, the VP7-mRNA vaccine was injected by subcutaneous or intramuscular routes into mice. Mice received three injections in 21 d intervals. IgG antibodies, neutralizing antibodies, cellular immunity, and gene expression from peripheral blood mononuclear cells were evaluated. Significant differences in levels of IgG antibodies were not observed in groups with adjuvant but were observed in groups without adjuvant. The vaccine without adjuvant induced the highest antibody titers after intramuscular injection. The vaccine elicited a potent antiviral immune response characterized by antiviral clusters of differentiation CD8+ T cells. VP7-mRNA induced interferon-γ secretion to mediate cellular immune responses. Chemokine-mediated signaling pathways and immune response were activated by VP7-mRNA vaccine injection. The mRNA LNP vaccine will require testing for protective efficacy, and it is an option for preventing rotavirus infection.


Assuntos
Infecções por Rotavirus , Vacinas contra Rotavirus , Rotavirus , Criança , Animais , Camundongos , Humanos , Pré-Escolar , Rotavirus/genética , Vacinas contra Rotavirus/genética , Vacinas de mRNA , RNA Mensageiro/genética , Linfócitos T CD8-Positivos , Leucócitos Mononucleares , Anticorpos Antivirais , Proteínas do Capsídeo/genética , Adjuvantes Imunológicos , Vacinas Atenuadas , Imunoglobulina G
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...