scholarly journals Dengue Virus Replicative Intermediate RNA Detection by Reverse Transcription-PCR

2002 ◽  
Vol 9 (1) ◽  
pp. 198-200 ◽  
Author(s):  
Gilberto Vaughan ◽  
Hiram Olivera ◽  
Leopoldo Santos-Argumedo ◽  
Abraham Landa ◽  
Baltasar Briseño ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Virus Replication ◽  
Reverse Transcription ◽  
Cell Tropism ◽  
Rna Detection ◽  
Replicative Intermediate ◽  
Reverse Transcription Pcr ◽  
Infected Cells

ABSTRACT Dengue virus replication involves synthesis of a replicative intermediate RNA (RI-RNA), whose presence reveals an actual infection. We report on a simple and rapid reverse transcription-PCR for the detection of viral RI-RNA in infected cells. The product is demonstrated at 20 min postinfection. This method is useful for the study of virus-cell tropism.

scholarly journals A Combined Genetic-Proteomic Approach Identifies Residues within Dengue Virus NS4B Critical for Interaction with NS3 and Viral Replication

2015 ◽  
Vol 89 (14) ◽  
pp. 7170-7186 ◽  
Author(s):  
Laurent Chatel-Chaix ◽  
Wolfgang Fischl ◽  
Pietro Scaturro ◽  
Mirko Cortese ◽  
Stephanie Kallis ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dengue Virus ◽  
Virus Replication ◽  
Strong Evidence ◽  
Drug Target ◽  
Nonstructural Protein ◽  
Rna Replication ◽  
Replication Cycle ◽  
Infected Cells ◽  
Ns3 Protease

ABSTRACTDengue virus (DENV) infection causes the most prevalent arthropod-borne viral disease worldwide. Approved vaccines are not available, and targets suitable for the development of antiviral drugs are lacking. One possible drug target is nonstructural protein 4B (NS4B), because it is absolutely required for virus replication; however, its exact role in the DENV replication cycle is largely unknown. With the aim of mapping NS4B determinants critical for DENV replication, we performed a reverse genetic screening of 33 NS4B mutants in the context of an infectious DENV genome. While the majority of these mutations were lethal, for several of them, we were able to select for second-site pseudoreversions, most often residing in NS4B and restoring replication competence. To identify all viral NS4B interaction partners, we engineered a fully viable DENV genome encoding an affinity-tagged NS4B. Mass spectrometry-based analysis of the NS4B complex isolated from infected cells identified the NS3 protease/helicase as a major interaction partner of NS4B. By combining the genetic complementation map of NS4B with a replication-independent expression system, we identified the NS4B cytosolic loop—more precisely, amino acid residue Q134—as a critical determinant for NS4B-NS3 interaction. An alanine substitution at this site completely abrogated the interaction and DENV RNA replication, and both were restored by pseudoreversions A69S and A137V. This strict correlation between the degree of NS4B-NS3 interaction and DENV replication provides strong evidence that this viral protein complex plays a pivotal role during the DENV replication cycle, hence representing a promising target for novel antiviral strategies.IMPORTANCEWith no approved therapy or vaccine against dengue virus infection, the viral nonstructural protein 4B (NS4B) represents a possible drug target, because it is indispensable for virus replication. However, little is known about its precise structure and function. Here, we established the first comprehensive genetic interaction map of NS4B, identifying amino acid residues that are essential for virus replication, as well as second-site mutations compensating for their defects. Additionally, we determined the NS4B viral interactome in infected cells and identified the NS3 protease/helicase as a major interaction partner of NS4B. We mapped residues in the cytosolic loop of NS4B as critical determinants for interaction with NS3, as well as RNA replication. The strong correlation between NS3-NS4B interaction and RNA replication provides strong evidence that this complex plays a pivotal role in the viral replication cycle, hence representing a promising antiviral drug target.

scholarly journals Dengue virus sustains viability of infected cells by counteracting apoptosis-mediated DNA breakage

2020 ◽  
Author(s):  
Himadri Nath ◽  
Keya Basu ◽  
Abhishek De ◽  
Subhajit Biswas
Keyword(s):  
Dengue Virus ◽  
Virus Replication ◽  
Host Cells ◽  
Severe Dengue ◽  
Dna Breaks ◽  
Dna Breakage ◽  
Major Player ◽  
Infected Cells ◽  
Dna Break ◽  
Cellular Dna

AbstractDengue is the most important arboviral disease inflicting mankind. This mosquito-borne Flavivirus causes mild to severe dengue fever which in some cases leads to life-threatening conditions namely, dengue haemorrhagic fever and dengue shock syndrome. Annual infection is estimated at 390 million globally with 96 million manifesting clinically. So, ≥80% infections are asymptomatic and self-limiting. Dengue virus (DV) non-structural protein 1 (NS1) is a proven virotoxin abundantly present in the victim’s blood. We found that DV-infected or only NS1-expressing cells both can induce Cleaved Caspase3, due to antiviral response of host cells. NS1-transfected cells also showed nuclear damage and significant levels of DNA breaks suggestive of ensuing apoptosis. So, it was established that NS1 alone is capable of causing apoptosis. Surprisingly, despite secreting similar amount of soluble NS1, the DV-infected cells showed intact nuclear morphology and background levels of DNA nicks. These observations suggested that DV downregulates apoptosis of infected cells, which is a viral strategy against host defence. Furthermore, DV-infected cells counteracted Camptothecin-induced apoptotic DNA break. DV-infection was also found to keep the infected cells metabolically more active than only NS1 expressing cells. So, DV bypasses cellular defence against virus i.e. apoptosis by counteracting cellular DNA break and keeps the infected cells metabolically active to support virus replication for longer period which eventually results in high virus titer in circulation. Our findings reveal another level of intricacy involving dengue virus-host interactions and perhaps explain why ≥80% DV infections are asymptomatic/self-limiting despite the presence of NS1 virotoxin in infected cells.Author SummaryNS1, a virotoxin, abundantly present in Dengue patients blood, is a major player behind disease patho-biogenesis including plasma leakage. Despite the presence of NS1 in blood, Dengue is asymptomatic and self-limiting in more than 80% dengue virus (DV) infected people. We investigated this observation and found that plasmid-mediated NS1 expression and secretion in cells are sufficient to cause programmed cell death (apoptosis) and associated cellular DNA breakage. However, cells infected with dengue virus and secreting equivalent amounts of NS1 didn’t exhibit apoptotic DNA breakage. Consequently, DV-infected cells showed better survival than cells in which only NS1 was transiently expressed by transfection with expression plasmid. We also found that DV can even prevent chemical induced apoptotic DNA damage in infected host cells. So, DV bypasses host antiviral defence i.e. apoptosis by counteracting cellular DNA breakages and keeps the infected cells metabolically active to prolong virus replication.

scholarly journals Wolbachia wStri Blocks Zika Virus Growth at Two Independent Stages of Viral Replication

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
M. J. Schultz ◽  
A. L. Tan ◽  
C. N. Gray ◽  
S. Isern ◽  
S. F. Michael ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Viral Replication ◽  
Yellow Fever ◽  
Virus Replication ◽  
Zika Virus ◽  
Chikungunya Virus ◽  
Yellow Fever Virus ◽  
Rna Viruses ◽  
Content Type ◽  
Infected Cells

ABSTRACTMosquito-transmitted viruses are spread globally and present a great risk to human health. Among the many approaches investigated to limit the diseases caused by these viruses are attempts to make mosquitos resistant to virus infection. Coinfection of mosquitos with the bacteriumWolbachia pipientisfrom supergroup A is a recent strategy employed to reduce the capacity for major vectors in theAedesmosquito genus to transmit viruses, including dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Recently, a supergroup BWolbachia wStri, isolated fromLaodelphax striatellus, was shown to inhibit multiple lineages of ZIKV inAedes albopictuscells. Here, we show thatwStri blocks the growth of positive-sense RNA viruses DENV, CHIKV, ZIKV, and yellow fever virus by greater than 99.9%.wStri presence did not affect the growth of the negative-sense RNA viruses LaCrosse virus or vesicular stomatitis virus. Investigation of the stages of the ZIKV life cycle inhibited bywStri identified two distinct blocks in viral replication. We found a reduction of ZIKV entry intowStri-infected cells. This was partially rescued by the addition of a cholesterol-lipid supplement. Independent of entry, transfected viral genome was unable to replicate inWolbachia-infected cells. RNA transfection and metabolic labeling studies suggested that this replication defect is at the level of RNA translation, where we saw a 66% reduction in mosquito protein synthesis inwStri-infected cells. This study’s findings increase the potential for application ofwStri to block additional arboviruses and also identify specific blocks in viral infection caused byWolbachiacoinfection.IMPORTANCEDengue, Zika, and yellow fever viruses are mosquito-transmitted diseases that have spread throughout the world, causing millions of infections and thousands of deaths each year. Existing programs that seek to contain these diseases through elimination of the mosquito population have so far failed, making it crucial to explore new ways of limiting the spread of these viruses. Here, we show that introduction of an insect symbiont,Wolbachia wStri, into mosquito cells is highly effective at reducing yellow fever virus, dengue virus, Zika virus, and Chikungunya virus production. Reduction of virus replication was attributable to decreases in entry and a strong block of virus gene expression at the translational level. These findings expand the potential use ofWolbachia wStri to block viruses and identify two separate steps for limiting virus replication in mosquitos that could be targeted via microbes or other means as an antiviral strategy.

scholarly journals Styrylquinolines, Integrase Inhibitors Acting Prior to Integration: a New Mechanism of Action for Anti-Integrase Agents

2004 ◽  
Vol 78 (11) ◽  
pp. 5728-5736 ◽  
Author(s):  
Sabine Bonnenfant ◽  
Claire Marie Thomas ◽  
Claudio Vita ◽  
Frédéric Subra ◽  
Eric Deprez ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Transcriptase Inhibitor ◽  
Integrase Inhibitors ◽  
Integrase Gene ◽  
Reverse Transcription Pcr ◽  
Cellular Target ◽  
Infected Cells ◽  
Reverse Transcriptase Inhibitor ◽  
First Time

ABSTRACT We have previously shown that styrylquinolines (SQLs) are integrase inhibitors in vitro. They compete with the long terminal repeat substrate for integrase. Here, we describe the cellular mode of action of these molecules. We show that SQLs do not interfere with virus entry. In fact, concentrations of up to 20 times the 50% inhibitory concentration did not inhibit cell-to-cell fusion or affect the interaction between GP120 and CD4 in vitro. Moreover, the pseudotype of the retrovirus envelope did not affect drug activity. Quantitative reverse transcription PCR experiments showed that SQLs do not inhibit the entry of the genomic RNA. In contrast, the treatment of human immunodeficiency virus type 1-infected cells with SQLs reduced the amount of the late cDNA, suggesting for the first time that integrase targeting molecules may affect the accumulation of DNA during reverse transcription. The cellular target of SQLs was confirmed by the appearance of mutations in the integrase gene when viruses were grown in the presence of increasing concentrations of SQLs. Finally, these mutations led to SQL-resistant viruses when introduced into the wild-type sequence. In contrast, SQLs were fully active against reverse transcriptase inhibitor- and diketo acid-resistant viruses, positioning SQLs as a second group of anti-integrase compounds.

scholarly journals Identification of Proteins Bound to Dengue Viral RNA In Vivo Reveals New Host Proteins Important for Virus Replication

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Stacia L. Phillips ◽  
Erik J. Soderblom ◽  
Shelton S. Bradrick ◽  
Mariano A. Garcia-Blanco
Keyword(s):  
Mass Spectrometry ◽  
Dengue Virus ◽  
Virus Replication ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Viral Rna ◽  
Host Proteins ◽  
Infected Cells

ABSTRACT Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Due to the limited coding capacity of the viral genome and the complexity of the viral life cycle, host cell proteins play essential roles throughout the course of viral infection. Host RNA-binding proteins mediate various aspects of virus replication through their physical interactions with viral RNA. Here we describe a technique designed to identify such interactions in the context of infected cells using UV cross-linking followed by antisense-mediated affinity purification and mass spectrometry. Using this approach, we identified interactions, several of them novel, between host proteins and dengue viral RNA in infected Huh7 cells. Most of these interactions were subsequently validated using RNA immunoprecipitation. Using small interfering RNA (siRNA)-mediated gene silencing, we showed that more than half of these host proteins are likely involved in regulating virus replication, demonstrating the utility of this method in identifying biologically relevant interactions that may not be identified using traditional in vitro approaches. IMPORTANCE Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Viral RNA molecules physically interact with cellular RNA-binding proteins (RBPs) throughout the course of infection; the identification of such interactions will lead to the elucidation of the molecular mechanisms of virus replication. Until now, the identification of host proteins bound to dengue viral RNA has been accomplished using in vitro strategies. Here, we used a method for the specific purification of dengue viral ribonucleoprotein (RNP) complexes from infected cells and subsequently identified the associated proteins by mass spectrometry. We then validated a functional role for the majority of these proteins in mediating efficient virus replication. This approach has broad relevance to virology and RNA biology, as it could theoretically be used to purify any viral RNP complex of interest.

scholarly journals Human Immunodeficiency Virus Type 1 Integrase Protein Promotes Reverse Transcription through Specific Interactions with the Nucleoprotein Reverse Transcription Complex

1999 ◽  
Vol 73 (3) ◽  
pp. 2126-2135 ◽  
Author(s):  
Xiaoyun Wu ◽  
Hongmei Liu ◽  
Hongling Xiao ◽  
Joan A. Conway ◽  
Eric Hehl ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Virus Replication ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Reverse Transcription ◽  
Specific Interactions ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Integrase Protein

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) integrase protein (IN) is essential for integration of the viral DNA into host cell chromosomes. Since IN is expressed and assembled into virions as part of the 160-kDa Gag-Pol precursor polyprotein and catalyzes integration of the provirus in infected cells as a mature 32-kDa protein, mutations in IN are pleiotropic and may affect virus replication at different stages of the virus life cycle in addition to integration. Several different phenotypes have been observed for IN mutant viruses, including defects in virion morphology, protein composition, reverse transcription, nuclear import, and integration. Because the effects of mutations in the IN domain of Gag-Pol can not always be distinguished from those of mutations in the mature IN protein, there remains a significant gap in our understanding of IN function in vivo. To directly analyze the function of the mature IN protein itself, in the context of a replicating virus but independently from that of Gag-Pol, we used an approach developed in our laboratory for incorporating proteins into HIV virions by their expression in trans as fusion partners of either Vpr or Vpx. By providing IN intrans as a Vpr-IN fusion protein, our analysis revealed, for the first time, that the mature IN protein is essential for the efficient initiation of reverse transcription in infected cells and that this function does not require the IN protein to be enzymatically (integration) active. Our findings of a direct physical interaction between IN and reverse transcriptase and the failure of heterologous HIV-2 IN protein to efficiently support reverse transcription indicate that this novel function occurs through specific interactions with other viral components of the reverse transcription initiation complex. Studies involving complementation between integration- and DNA synthesis-defective IN mutants further support this conclusion and reveal that the highly conserved HHCC motif of IN is important for both activities. These findings provide important new insights into IN function and reverse transcription in the context of the nucleoprotein reverse transcription complex within the infected cell. Moreover, they validate a novel approach that obviates the need to mutate Gag-Pol in order to study the role of its individual mature components at the virus replication level.

scholarly journals Internally Controlled, Multiplex Real-Time Reverse Transcription PCR for Dengue Virus and Yellow Fever Virus Detection

2018 ◽  
Vol 98 (6) ◽  
pp. 1833-1836 ◽  
Author(s):  
Alejandra Rojas ◽  
Cheikh T. Diagne ◽  
Victoria D. Stittleburg ◽  
Alisha Mohamed-Hadley ◽  
Yvalena Arévalo de Guillén ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Yellow Fever ◽  
Reverse Transcription ◽  
Yellow Fever Virus ◽  
Virus Detection ◽  
Fever Virus ◽  
Reverse Transcription Pcr

scholarly journals Detection and differentiation of dengue virus serotypes by one-step multiplex reverse transcription PCR assays

2020 ◽  
Vol 6 (1) ◽  
pp. 227-246
Author(s):  
Mariana Maryelle Ferreira Sousa ◽  
Bruna de Oliveira Melo ◽  
Antonia Khaynnam Silva Costa ◽  
Jadna Patricia Pinheiro Nunes ◽  
Silvio Gomes Monteiro ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Reverse Transcription ◽  
Reverse Transcription Pcr ◽  
One Step ◽  
Dengue Virus Serotypes ◽  
Pcr Assays

scholarly journals Quantitative Competitive Reverse Transcription-PCR for Quantification of Dengue Virus RNA

2000 ◽  
Vol 38 (9) ◽  
pp. 3306-3310 ◽  
Author(s):  
Wei-Kung Wang ◽  
Chun-Nan Lee ◽  
Chuan-Liang Kao ◽  
Yi-Ling Lin ◽  
Chwan-Chuen King
Keyword(s):  
Dengue Virus ◽  
Internal Control ◽  
Reverse Transcription ◽  
Virus Titer ◽  
Accurate Method ◽  
Pcr Assay ◽  
Dengue Virus Infection ◽  
Reverse Transcription Pcr ◽  
Virus Rna ◽  
Dengue Virus Serotypes

A quantitative competitive reverse transcription-PCR assay was developed to quantify dengue virus RNA in this study. The main features include a primer pair targeting a highly conserved region in the capsid and the addition of competing RNA that contains an internal deletion to provide a stringent internal control for quantification. It can be utilized to quantify RNA isolated from the four dengue virus serotypes but not RNA isolated from other flaviviruses, including Japanese encephalitis virus and hepatitis C virus, both prevalent in Asia. It can also be used to quantify dengue virus RNA isolated from the plasma of infected individuals. The sensitivity of the assay was estimated to be 10 to 50 copies of RNA per reaction, and twofold differences in virus titer are distinguishable. This assay is a convenient, sensitive, and accurate method for quantification and can be used to further understanding of the pathogenesis of dengue virus infection.

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