Dengue virus life cycle: viral and host factors modulating infectivity

2010 ◽  
Vol 67 (16) ◽  
pp. 2773-2786 ◽  
Author(s):  
Izabela A. Rodenhuis-Zybert ◽  
Jan Wilschut ◽  
Jolanda M. Smit
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Host Factors ◽  
Virus Life Cycle

scholarly journals Scanning Mutagenesis Studies Reveal a Potential Intramolecular Interaction within the C-Terminal Half of Dengue Virus NS2A Involved in Viral RNA Replication and Virus Assembly and Secretion

2015 ◽  
Vol 89 (8) ◽  
pp. 4281-4295 ◽  
Author(s):  
Ren-Huang Wu ◽  
Ming-Han Tsai ◽  
Day-Yu Chao ◽  
Andrew Yueh
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Virus Assembly ◽  
Intramolecular Interaction ◽  
Rna Replication ◽  
The Other ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Transmembrane Segments ◽  
Virus Life Cycle

ABSTRACTThe NS2A protein of dengue virus (DENV) has eight predicted transmembrane segments (pTMSs; pTMS1 to pTMS8). NS2A has been shown to participate in RNA replication, virion assembly, and the host antiviral response. However, the role of the amino acid residues within the pTMS regions of NS2A during the virus life cycle is poorly understood. In the study described here, we explored the function of DENV NS2A by introducing a series of double or triple alanine substitutions into the C-terminal half (pTMS4 to pTMS8) of NS2A in the context of a DENV infectious clone or subgenomic replicon. Fourteen (8 within pTMS8) of 35 NS2A mutants displayed a lethal phenotype due to impairment of RNA replication by a replicon assay. Three NS2A mutants with mutations within pTMS7, the CM20, CM25, and CM27 mutants, displayed similar phenotypes, low virus yields (>100-fold reduction), wild-type-like replicon activity, and low infectious virus-like particle yields by transienttrans-packaging experiments, suggesting a defect in virus assembly and secretion. The sequencing of revertant viruses derived from CM20, CM25, and CM27 mutant viruses revealed a consensus reversion mutation, leucine (L) to phenylalanine (F), at codon 181 within pTMS7. The introduction of an L181F mutation into a full-length NS2A mutant, i.e., the CM20, CM25, and CM27 constructs, completely restored wild-type infectivity. Notably, L181F also substantially rescued the other severely RNA replication-defective mutants with mutations within pTMS4, pTMS6, and pTMS8, i.e., the CM2, CM3, CM13, CM31, and CM32 mutants. In conclusion, the results revealed the essential roles of pTMS4 to pTMS8 of NS2A in RNA replication and/or virus assembly and secretion. The intramolecular interaction between pTMS7 and pTMS4, pTMS6, or pTMS8 of the NS2A protein was also implicated.IMPORTANCEThe reported characterization of the C-terminal half of dengue virus NS2A is the first comprehensive mutagenesis study to investigate the function of flavivirus NS2A involved in the steps of the virus life cycle. In particular, detailed mapping of the amino acid residues within the predicted transmembrane segments (pTMSs) of NS2A involved in RNA replication and/or virus assembly and secretion was performed. A revertant genetics study also revealed that L181F within pTMS7 is a consensus reversion mutation that rescues both RNA replication-defective and virus assembly- and secretion-defective mutants with mutations within the other three pTMSs of NS2A. Collectively, these findings elucidate the role played by NS2A during the virus life cycle, possibly through the intricate intramolecular interaction between pTMS7 and other pTMSs within the NS2A protein.

scholarly journals Neutralization of Acidic Intracellular Vesicles by Niclosamide Inhibits Multiple Steps of the Dengue Virus Life Cycle In Vitro

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Eunhye Jung ◽  
Sangwoo Nam ◽  
Hyeryeon Oh ◽  
Sangmi Jun ◽  
Hyun-Joo Ro ◽  
...  
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Virus Life Cycle ◽  
Intracellular Vesicles

scholarly journals RNA Helicase A Is an Important Host Factor Involved in Dengue Virus Replication

2018 ◽  
Vol 93 (4) ◽  
Author(s):  
Yi Wang ◽  
Xiaoyan Chen ◽  
Jiong Xie ◽  
Shili Zhou ◽  
Yanxia Huang ◽  
...  
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Zika Virus ◽  
Rna Helicase ◽  
Host Factor ◽  
Host Factors ◽  
Helicase Activity ◽  
Nonstructural Proteins ◽  
Rna Helicase A ◽  
Important Host

ABSTRACT Dengue virus (DENV) utilizes host factors throughout its life cycle. In this study, we identified RNA helicase A (RHA), a member of the DEAD/H helicase family, as an important host factor of DENV. In response to DENV2 infection, nuclear RHA protein was partially redistributed into the cytoplasm. The short interfering RNA-mediated knockdown of RHA significantly reduced the amounts of infectious viral particles in various cells. The RHA knockdown reduced the multistep viral growth of DENV2 and Japanese encephalitis virus but not Zika virus. Further study showed that the absence of RHA resulted in a reduction of both viral RNA and protein levels, and the data obtained from the reporter replicon assay indicated that RHA does not directly promote viral protein synthesis. RHA bound to the DENV RNA and associated with three nonstructural proteins, including NS1, NS2B3, and NS4B. Further study showed that different domains of RHA mediated its interaction with these viral proteins. The expression of RHA or RHA-K417R mutant protein lacking ATPase/helicase activity in RHA-knockdown cells successfully restored DENV2 replication levels, suggesting that the helicase activity of RHA is dispensable for its proviral effect. Overall, our work reveals that RHA is an important factor of DENV and might serve as a target for antiviral agents. IMPORTANCE Dengue, caused by dengue virus, is a rapidly spreading disease, and currently there are no treatments available. Host factors involved in the viral replication of dengue virus are potential antiviral therapeutic targets. Although RHA has been shown to promote the multiplication of several viruses, such as HIV and adenovirus, its role in the flavivirus family, including dengue virus, Japanese encephalitis virus, and emerging Zika virus, remains elusive. The current study revealed that RHA relocalized into the cytoplasm upon DENV infection and associated with viral RNA and nonstructural proteins, implying that RHA was actively engaged in the viral life cycle. We further provide evidence that RHA promoted the viral yields of DENV2 independent of its helicase activity. These findings demonstrated that RHA is a new host factor required for DENV replication and might serve as a target for antiviral drugs.

scholarly journals The Role of Capsid in the Early Steps of HIV-1 Infection: New Insights into the Core of the Matter

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1161
Author(s):  
Nawal Al Burtamani ◽  
Alwin Paul ◽  
Ariberto Fassati
Keyword(s):  
Life Cycle ◽  
Small Molecules ◽  
Reverse Transcription ◽  
Nuclear Import ◽  
Protein A ◽  
Host Factors ◽  
Virus Life Cycle ◽  
Experimental Approaches ◽  
Hiv 1

In recent years, major advances in research and experimental approaches have significantly increased our knowledge on the role of the HIV-1 capsid in the virus life cycle, from reverse transcription to integration and gene expression. This makes the capsid protein a good pharmacological target to inhibit HIV-1 replication. This review covers our current understanding of the role of the viral capsid in the HIV-1 life cycle and its interaction with different host factors that enable reverse transcription, trafficking towards the nucleus, nuclear import and integration into host chromosomes. It also describes different promising small molecules, some of them in clinical trials, as potential targets for HIV-1 therapy.

scholarly journals Revisiting dengue virus-mosquito interactions: molecular insights into viral fitness

2021 ◽  
Vol 102 (11) ◽  
Author(s):  
Tanamas Siriphanitchakorn ◽  
R. Manjunatha Kini ◽  
Eng Eong Ooi ◽  
Milly M. Choy
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Denv Infection ◽  
Viral Fitness ◽  
Host Factors ◽  
Mammalian Host ◽  
Mosquito Vectors ◽  
Host Interactions ◽  
Cellular Processes ◽  
Natural Hosts

Dengue virus (DENV), like other viruses, closely interacts with the host cell machinery to complete its life cycle. Over the course of infection, DENV interacts with several host factors with pro-viral activities to support its infection. Meanwhile, it has to evade or counteract host factors with anti-viral activities which inhibit its infection. These molecular virus-host interactions play a crucial role in determining the success of DENV infection. Deciphering such interactions is thus paramount to understanding viral fitness in its natural hosts. While DENV-mammalian host interactions have been extensively studied, not much has been done to characterize DENV-mosquito host interactions despite its importance in controlling DENV transmission. Here, to provide a snapshot of our current understanding of DENV-mosquito interactions, we review the literature that identified host factors and cellular processes related to DENV infection in its mosquito vectors, Aedes aegypti and Aedes albopictus, with a particular focus on DENV-mosquito omics studies. This knowledge provides fundamental insights into the DENV life cycle, and could contribute to the development of novel antiviral strategies.

scholarly journals Valosin-containing protein/p97 plays critical roles in the Japanese encephalitis virus life cycle

2021 ◽  
Author(s):  
Sapna Sehrawat ◽  
Renu Khasa ◽  
Arundhati Deb ◽  
Surendra Kumar Prajapat ◽  
Suvadip Mallick ◽  
...  
Keyword(s):  
Life Cycle ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Host Factor ◽  
Encephalitis Virus ◽  
Host Factors ◽  
Viral Rna ◽  
High Morbidity ◽  
Replication Complex ◽  
Virus Life Cycle

Host factors provide critical support for every aspect of the virus life cycle. We recently identified the valosin-containing protein (VCP)/p97, an abundant cellular ATPase with diverse cellular functions, as a host factor important for Japanese encephalitis virus (JEV) replication. In cultured cells, using siRNA-mediated protein depletion and pharmacological inhibitors, we show that VCP is crucial for replication of three flaviviruses: JEV, Dengue, and West Nile viruses. An FDA-approved VCP inhibitor, CB-5083, extended survival of mice in the animal model of JEV infection. While VCP depletion did not inhibit JEV attachment on cells, it delayed capsid degradation, potentially through the entrapment of the endocytosed virus in clathrin-coated vesicles (CCVs). Early during infection, VCP-depleted cells showed an increased colocalization of JEV capsid with clathrin, and also higher viral RNA levels in purified CCVs. We show that VCP interacts with the JEV nonstructural protein NS5 and is an essential component of the virus replication complex. The depletion of the major VCP cofactor UFD-1 also significantly inhibited JEV replication. Mechanistically, thus, VCP affected two crucial steps of the JEV life cycle – nucleocapsid release and RNA replication. Our study establishes VCP as a common host factor with a broad antiviral potential against flaviviruses. Importance JEV is the leading cause of viral encephalitis epidemics in South-east Asia, affecting majorly children with high morbidity and mortality. Identification of host factors is thus essential for the rational design of anti-virals that are urgently need as therapeutics. Here we have identified the VCP protein as one such host-factor. This protein is highly abundant in cells and engages in diverse functions and cellular pathways by its ability to interact with different co-factors. Using siRNA mediated protein knockdown, we show that this protein is essential for release of the viral RNA into the cell so that it can initiate replication. The protein plays a second crucial role for the formation of the JEV replication complex. FDA-approved drugs targeting VCP show enhanced mouse survival in JE model of disease, suggesting that this could be a druggable target for flavivirus infections.

scholarly journals A Genome-Wide CRISPR-Cas9 Screen Identifies the Dolichol-Phosphate Mannose Synthase Complex as a Host Dependency Factor for Dengue Virus Infection

2020 ◽  
Vol 94 (7) ◽  
Author(s):  
Athena Labeau ◽  
Etienne Simon-Loriere ◽  
Mohamed-Lamine Hafirassou ◽  
Lucie Bonnet-Madin ◽  
Sarah Tessier ◽  
...  
Keyword(s):  
Life Cycle ◽  
Dengue Virus ◽  
Zika Virus ◽  
Denv Infection ◽  
Host Factors ◽  
Viral Rna ◽  
Health Concern ◽  
Dengue Disease ◽  
Genome Wide ◽  
A Genome

ABSTRACT Dengue virus (DENV) is a mosquito-borne flavivirus responsible for dengue disease, a major human health concern for which no specific therapies are available. Like other viruses, DENV relies heavily on the host cellular machinery for productive infection. In this study, we performed a genome-wide CRISPR-Cas9 screen using haploid HAP1 cells to identify host genes important for DENV infection. We identified DPM1 and -3, two subunits of the endoplasmic reticulum (ER) resident dolichol-phosphate mannose synthase (DPMS) complex, as host dependency factors for DENV and other related flaviviruses, such as Zika virus (ZIKV). The DPMS complex catalyzes the synthesis of dolichol-phosphate mannose (DPM), which serves as mannosyl donor in pathways leading to N-glycosylation, glycosylphosphatidylinositol (GPI) anchor biosynthesis, and C- or O-mannosylation of proteins in the ER lumen. Mutation in the DXD motif of DPM1, which is essential for its catalytic activity, abolished DPMS-mediated DENV infection. Similarly, genetic ablation of ALG3, a mannosyltransferase that transfers mannose to lipid-linked oligosaccharide (LLO), rendered cells poorly susceptible to DENV. We also established that in cells deficient for DPMS activity, viral RNA amplification is hampered and truncated oligosaccharides are transferred to the viral prM and E glycoproteins, affecting their proper folding. Overall, our study provides new insights into the host-dependent mechanisms of DENV infection and supports current therapeutic approaches using glycosylation inhibitors to treat DENV infection. IMPORTANCE Dengue disease, which is caused by dengue virus (DENV), has emerged as the most important mosquito-borne viral disease in humans and is a major global health concern. DENV encodes only few proteins and relies on the host cell machinery to accomplish its life cycle. The identification of the host factors important for DENV infection is needed to propose new targets for antiviral intervention. Using a genome-wide CRISPR-Cas9 screen, we identified DPM1 and -3, two subunits of the DPMS complex, as important host factors for the replication of DENV as well as other related viruses such as Zika virus. We established that DPMS complex plays dual roles during viral infection, both regulating viral RNA replication and promoting viral structural glycoprotein folding/stability. These results provide insights into the host molecules exploited by DENV and other flaviviruses to facilitate their life cycle.

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