-
Heliyon Jun 2024Biocontainment regulations restrict the research on NiV to BSL-4 laboratories, thus limiting the mechanistic studies related to viral entry and allied pathogenesis....
Biocontainment regulations restrict the research on NiV to BSL-4 laboratories, thus limiting the mechanistic studies related to viral entry and allied pathogenesis. Understanding the precise process of viral-particle production and host cell entry is critical for designing targeted therapies or particle-based vaccines. In this study, we have synthesized HiBiT-tagged-NiV-VLPs to ease BSL-2 particle handling. We propose a simple yet effective approach of generating substantial amount of HiBiT-tagged NiV-VLPs by co-expressing viral structural proteins in HEK293T cells. Though homologous to parent virus, the incapacitated replication potential facilitates a BSL-2 handling of these particles. The inclusion of a highly sensitive HiBiT tag on these VLPs allows for a quick detection of viral binding and entry, as well as in assessing the efficiency of neutralizing antibodies using the NanoBiT technology. The HiBiT-tag binds in high affinity with LgBiT (Large BiT an 18 kDa fusion protein and complementary subunit of HiBiT peptide), and the resultant complex elicits high intensity luminescence in the presence of substrate. The VLPs produced were morphologically and functionally identical to the native virus, and the HiBiT-tag permitted their quick application in viral binding, entry, and antibody neutralization assays. "Thus, we report a simple setting for generating HiBiT-NiV VLPs which can be utilized in a BSL-2 laboratory, to concurrently quantify features of NiV assembly, binding and entry. This also offers an alternate-safe and effective platform for viral based antibody neutralization assays
PubMed: 38868026
DOI: 10.1016/j.heliyon.2024.e31905 -
The Journal of Biological Chemistry Jun 2024Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a lipid-enveloped virus that acquires its lipid bilayer from the host cell it infects. SARS-CoV-2 can...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a lipid-enveloped virus that acquires its lipid bilayer from the host cell it infects. SARS-CoV-2 can spread from cell to cell or from patient to patient by undergoing assembly and budding to form new virions. The assembly and budding of SARS-CoV-2 is mediated by several structural proteins known as envelope (E), membrane (M), nucleoprotein (N) and spike (S), which can form virus-like particles (VLPs) when co-expressed in mammalian cells. Assembly and budding of SARS-CoV-2 from the host ER-Golgi intermediate compartment is a critical step in the virus acquiring its lipid bilayer. To date, little information is available on how SARS-CoV-2 assembles and forms new viral particles from host membranes. In this study, we used several lipid binding assays and found the N protein can strongly associate with anionic lipids including phosphoinositides and phosphatidylserine. Moreover, we show lipid binding occurs in the N protein C-terminal domain, which is supported by extensive in silico analysis. We demonstrate anionic lipid binding occurs for both the free and N oligomeric forms, suggesting N can associate with membranes in the nucleocapsid form. Based on these results, we present a lipid-dependent model based on in vitro, cellular and in silico data for the recruitment of N to assembly sites in the lifecycle of SARS-CoV-2.
PubMed: 38866325
DOI: 10.1016/j.jbc.2024.107456 -
Revista Do Instituto de Medicina... 2024The group-specific antigen (gag) plays a crucial role in the assembly, release, and maturation of HIV. This study aimed to analyze the partial sequence of the HIV gag...
The group-specific antigen (gag) plays a crucial role in the assembly, release, and maturation of HIV. This study aimed to analyze the partial sequence of the HIV gag gene to classify HIV subtypes, identify recombination sites, and detect protease inhibitor (PI) resistance-associated mutations (RAMs). The cohort included 100 people living with HIV (PLH) who had experienced antiretroviral treatment failure with reverse transcriptase/protease inhibitors. Proviral HIV-DNA was successfully sequenced in 96 out of 100 samples for gag regions, specifically matrix (p17) and capsid (p24). Moreover, from these 96 sequences, 82 (85.42%) were classified as subtype B, six (6.25%) as subtype F1, one (1.04%) as subtype C, and seven (7.29%) exhibited a mosaic pattern between subtypes B and F1 (B/F1), with breakpoints at p24 protein. Insertions and deletions of amino acid at p17 were observed in 51 samples (53.13%). The prevalence of PI RAM in the partial gag gene was observed in 78 out of 96 PLH (81.25%). Among these cases, the most common mutations were R76K (53.13%), Y79F (31.25%), and H219Q (14.58%) at non-cleavage sites, as well as V128I (10.42%) and Y132F (11.46%) at cleavage sites. While B/F1 recombination was identified in the p24, the p17 coding region showed higher diversity, where insertions, deletions, and PI RAM, were observed at high prevalence. In PLH with virological failure, the analysis of the partial gag gene could contribute to more accurate predictions in genotypic resistance to PIs. This can aid guide more effective HIV treatment strategies.
Topics: Humans; HIV-1; HIV Infections; Genetic Variation; Male; gag Gene Products, Human Immunodeficiency Virus; Female; Adult; Drug Resistance, Multiple, Viral; Mutation; Genotype; Anti-HIV Agents; Middle Aged; Phylogeny; DNA, Viral
PubMed: 38865573
DOI: 10.1590/S1678-9946202466035 -
PLoS Pathogens Jun 2024Many plant arboviruses are persistently transmitted by piercing-sucking insect vectors. However, it remains largely unknown how conserved insect Toll immune response...
Many plant arboviruses are persistently transmitted by piercing-sucking insect vectors. However, it remains largely unknown how conserved insect Toll immune response exerts antiviral activity and how plant viruses antagonize it to facilitate persistent viral transmission. Here, we discover that southern rice black-streaked dwarf virus (SRBSDV), a devastating planthopper-transmitted rice reovirus, activates the upstream Toll receptors expression but suppresses the downstream MyD88-Dorsal-defensin cascade, resulting in the attenuation of insect Toll immune response. Toll pathway-induced the small antibacterial peptide defensin directly interacts with viral major outer capsid protein P10 and thus binds to viral particles, finally blocking effective viral infection in planthopper vector. Furthermore, viral tubular protein P7-1 directly interacts with and promotes RING E3 ubiquitin ligase-mediated ubiquitinated degradation of Toll pathway adaptor protein MyD88 through the 26 proteasome pathway, finally suppressing antiviral defensin production. This virus-mediated attenuation of Toll antiviral immune response to express antiviral defensin ensures persistent virus infection without causing evident fitness costs for the insects. E3 ubiquitin ligase also is directly involved in the assembly of virus-induced tubules constructed by P7-1 to facilitate viral spread in planthopper vector, thereby acting as a pro-viral factor. Together, we uncover a previously unknown mechanism used by plant arboviruses to suppress Toll immune response through the ubiquitinated degradation of the conserved adaptor protein MyD88, thereby facilitating the coexistence of arboviruses with their vectors in nature.
Topics: Animals; Arboviruses; Toll-Like Receptors; Insect Vectors; Signal Transduction; Plant Diseases; Reoviridae; Hemiptera; Oryza; Insect Proteins; Immunity, Innate
PubMed: 38865374
DOI: 10.1371/journal.ppat.1012318 -
Macromolecular Bioscience Jun 2024The phenomenon of RNA virus self-organization, first observed in the mid-20th century in tobacco mosaic virus, is the subject of extensive research. Efforts to... (Review)
Review
The phenomenon of RNA virus self-organization, first observed in the mid-20th century in tobacco mosaic virus, is the subject of extensive research. Efforts to comprehend this process intensify due to its potential for producing vaccines or antiviral compounds as well as nanocarriers and nanotemplates. However, direct observation of the self-assembly is hindered by its prevalence within infected host cells. One of the approaches involves in vitro and in silico research using model viruses featuring a ssRNA(+) genome enclosed within a capsid made up of a single type protein. While various pathways are proposed based on these studies, their relevance in vivo remains uncertain. On the other hand, the development of advanced microscopic methods provide insights into the events within living cells, where following viral infection, specialized compartments form to facilitate the creation of nascent virions. Intriguingly, a growing body of evidence indicates that the primary function of packaging signals in viral RNA is to effectively initiate the virion self-assembly. This is in contrast to earlier opinions suggesting a role in marking RNA for encapsidation. Another noteworthy observation is that many viruses undergo self-assembly within membraneless liquid organelles, which are specifically induced by viral proteins.
PubMed: 38864315
DOI: 10.1002/mabi.202400088 -
MBio Jun 2024Mammalian AIM-2-like receptor (ALR) proteins bind nucleic acids and initiate production of type I interferons or inflammasome assembly, thereby contributing to host...
Mammalian AIM-2-like receptor (ALR) proteins bind nucleic acids and initiate production of type I interferons or inflammasome assembly, thereby contributing to host innate immunity. In mice, the locus is highly polymorphic at the sequence and copy number level, and we show here that it is one of the most dynamic regions of the genome. One rapidly evolving gene within this region, , was introduced to the genome by gene conversion or an unequal recombination event a few million years ago. has a large, distinctive repeat region that differs in sequence and length among species and even closely related inbred strains. We show that IFI207 controls murine leukemia virus (MLV) infection and that it plays a role in the STING-mediated response to cGAMP, dsDNA, DMXXA, and MLV. IFI207 binds to STING, and inclusion of its repeat region appears to stabilize STING protein. The locus and provide a clear example of the evolutionary innovation of gene function, possibly as a result of host-pathogen co-evolution.IMPORTANCEThe Red Queen hypothesis predicts that the arms race between pathogens and the host may accelerate evolution of both sides, and therefore causes higher diversity in virulence factors and immune-related proteins, respectively . The gene family in mice has undergone rapid evolution in the last few million years and includes the creation of two novel members, and , in particular, became highly divergent, with significant genetic changes between highly related inbred mice. IFI207 protein acts in the STING pathway and contributes to anti-retroviral resistance via a novel mechanism. The data show that under the pressure of host-pathogen coevolution in a dynamic locus, gene conversion and recombination between gene family members creates new genes with novel and essential functions that play diverse roles in biological processes.
PubMed: 38860764
DOI: 10.1128/mbio.01209-24 -
Zhonghua Gan Zang Bing Za Zhi =... May 2024Chronic hepatitis B virus (HBV) infection is one of the major public health issues of ongoing global concern. Due to inadequate understanding of the HBV life cycle,... (Review)
Review
Chronic hepatitis B virus (HBV) infection is one of the major public health issues of ongoing global concern. Due to inadequate understanding of the HBV life cycle, there is a lack of effective drugs to cure chronic hepatitis B. During HBV replication, covalently closed circular DNA (cccDNA) serves as the template for viral replication and can be transcribed to produce five viral RNAs of 3.5, 2.4, 2.1 kb and 0.7 kb in length, which are translated to produce HBeAg, core protein, polymerase (P) protein, HBsAg and HBx proteins, respectively. Among them, the 3.5 kb pregenomic RNA (pgRNA) is also the template for viral reverse transcription. Polymerase protein recognizes and binds to the capsid assembly signal on the pgRNA to initiate capsid assembly and reverse transcription. Recent studies have revealed that the processes of splicing, nuclear export, stability, translation, and pgRNA encapsidation of HBV RNAs are regulated by a post-transcriptional regulatory network within the host cell and depend on unique post-transcriptional regulatory elements in the HBV RNA structure. The aim of this review is to overview the post-transcriptional regulatory mechanisms of HBV RNA and their applications in the study of HBV antiviral therapeutics, with the aim of providing new ideas for the development of new drugs targeting HBV RNA.
Topics: Hepatitis B virus; RNA, Viral; Humans; Virus Replication; Antiviral Agents; Gene Expression Regulation, Viral; Hepatitis B, Chronic; RNA Processing, Post-Transcriptional
PubMed: 38858198
DOI: 10.3760/cma.j.cn501113-20240410-00191 -
Structure (London, England : 1993) Jun 2024In a recent issue of Nature, Coshic et al. employ a computational multiscale approach to package the complete HK97 viral genome into its capsid. They find both good...
In a recent issue of Nature, Coshic et al. employ a computational multiscale approach to package the complete HK97 viral genome into its capsid. They find both good agreement with experimental observations and shed new light on the heterogeneity of genome structures and the mechanism by which they package.
Topics: Capsid; Genome, Viral; Capsid Proteins; Virus Assembly; Molecular Dynamics Simulation; Models, Molecular
PubMed: 38848682
DOI: 10.1016/j.str.2024.05.009 -
Frontiers in Cellular and Infection... 2024Corona Virus Disease 2019 (COVID-19) is a highly prevalent and potent infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Until... (Review)
Review
Corona Virus Disease 2019 (COVID-19) is a highly prevalent and potent infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Until now, the world is still endeavoring to develop new ways to diagnose and treat COVID-19. At present, the clinical prevention and treatment of COVID-19 mainly targets the spike protein on the surface of SRAS-CoV-2. However, with the continuous emergence of SARS-CoV-2 Variants of concern (VOC), targeting the spike protein therapy shows a high degree of limitation. The Nucleocapsid Protein (N protein) of SARS-CoV-2 is highly conserved in virus evolution and is involved in the key process of viral infection and assembly. It is the most expressed viral structural protein after SARS-CoV-2 infection in humans and has high immunogenicity. Therefore, N protein as the key factor of virus infection and replication in basic research and clinical application has great potential research value. This article reviews the research progress on the structure and biological function of SARS-CoV-2 N protein, the diagnosis and drug research of targeting N protein, in order to promote researchers' further understanding of SARS-CoV-2 N protein, and lay a theoretical foundation for the possible outbreak of new and sudden coronavirus infectious diseases in the future.
Topics: SARS-CoV-2; Humans; Coronavirus Nucleocapsid Proteins; COVID-19; Phosphoproteins; Spike Glycoprotein, Coronavirus; Nucleocapsid Proteins
PubMed: 38846351
DOI: 10.3389/fcimb.2024.1415885 -
Alimentary Pharmacology & Therapeutics Jul 2024Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as... (Review)
Review
BACKGROUND
Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), whose global prevalence is rising.
AIMS
To review the histopathology of hepatic steatosis and its mechanisms of development and to identify common and rare disease associations.
METHODS
We reviewed literature on the basic science of lipid droplet (LD) biology and clinical research on acute and chronic liver diseases associated with hepatic steatosis using the PubMed database.
RESULTS
A variety of genetic and environmental factors contribute to the development of chronic hepatic steatosis or steatotic liver disease, which typically appears macrovesicular. Microvesicular steatosis is associated with acute mitochondrial dysfunction and liver failure. Fat metabolic processes in hepatocytes whose dysregulation leads to the development of steatosis include secretion of lipoprotein particles, uptake of remnant lipoprotein particles or free fatty acids from blood, de novo lipogenesis, oxidation of fatty acids, lipolysis and lipophagy. Hepatic insulin resistance is a key feature of MASLD. Seipin is a polyfunctional protein that facilitates LD biogenesis. Assembly of hepatitis C virus takes place on LD surfaces. LDs make important, functional contact with the endoplasmic reticulum and other organelles.
CONCLUSIONS
Diverse liver pathologies are associated with hepatic steatosis, with MASLD being the most important contributor. The biogenesis and dynamics of LDs in hepatocytes are complex and warrant further investigation. Organellar interfaces permit co-regulation of lipid metabolism to match generation of potentially toxic lipid species with their LD depot storage.
Topics: Humans; Chronic Disease; Fatty Liver; Liver Diseases; Non-alcoholic Fatty Liver Disease; Acute Disease; Lipid Metabolism; Liver
PubMed: 38845486
DOI: 10.1111/apt.18059