scholarly journals Differential viral RNA methylation contributes to pathogen blocking in Wolbachia-colonized arthropod

2021 ◽  
Author(s):  
Tamanash Bhattacharya ◽  
Liewei Yan ◽  
Hani Zaher ◽  
Irene L.G. Newton ◽  
Richard William Hardy
Keyword(s):  
Virus Replication ◽  
Ectopic Expression ◽  
Viral Rna ◽  
Progeny Virus ◽  
Virus Infectivity ◽  
Virus Inhibition ◽  
Mosquito Cells ◽  
Cytosine Methyltransferase ◽  
Mechanism Operative

Arthropod endosymbiont Wolbachia pipientis is part of a global biocontrol strategy aimed at reducing the spread of mosquito-borne RNA viruses such as alphaviruses. Our prior work examining Wolbachia-mediated pathogen blocking has demonstrated (i) the importance of a host cytosine methyltransferase, DNMT2, in Drosophila, and (ii) viral RNA as a target through which pathogen-blocking is mediated. Here we report on the role of DNMT2 in Wolbachia induced virus inhibition of alphaviruses in Aedes sp.. Mosquito DNMT2 levels were altered in the presence of both viruses and Wolbachia, albeit in opposite directions. Elevated levels of DNMT2 in mosquito salivary glands induced by virus infection were suppressed in Wolbachia colonized animals coincident with a reduction of virus replication, and decreased infectivity of progeny virus. Ectopic expression of DNMT2 in cultured Aedes cells was proviral increasing progeny virus infectivity, and this effect of DNMT2 on virus replication and infectivity was dependent on its methyltransferase activity. Finally, examination of the effects of Wolbachia on modifications of viral RNA by LC-MS showed a decrease in the amount of 5-methylcytosine modification consistent with the down-regulation of DNMT2 in Wolbachia colonized mosquito cells and animals. Collectively, our findings support the conclusion that disruption of 5-methylcytosine modification of viral RNA is an important mechanism operative in pathogen blocking. These data also emphasize the essential role of epitranscriptomic modifications in regulating fundamental processes of virus replication and transmission.

scholarly journals The Interferon-Induced Exonuclease ISG20 Exerts Antiviral Activity through Upregulation of Type I Interferon Response Proteins

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Christopher M. Weiss ◽  
Derek W. Trobaugh ◽  
Chengqun Sun ◽  
Tiffany M. Lucas ◽  
Michael S. Diamond ◽  
...  
Keyword(s):  
Virus Replication ◽  
Type I Interferon ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Viral Rna ◽  
Interferon Response ◽  
Type I ◽  
Venezuelan Equine Encephalitis ◽  
Wild Type ◽  
In Cells

ABSTRACTType I interferon (IFN)-stimulated genes (ISGs) have critical roles in inhibiting virus replication and dissemination. Despite advances in understanding the molecular basis of ISG restriction, the antiviral mechanisms of many remain unclear. The 20-kDa ISG ISG20 is a nuclear 3′–5′ exonuclease with preference for single-stranded RNA (ssRNA) and has been implicated in the IFN-mediated restriction of several RNA viruses. Although the exonuclease activity of ISG20 has been shown to degrade viral RNAin vitro, evidence has yet to be presented that virus inhibition in cells requires this activity. Here, we utilized a combination of an inducible, ectopic expression system and newly generatedIsg20−/−mice to investigate mechanisms and consequences of ISG20-mediated restriction. Ectopically expressed ISG20 localized primarily to Cajal bodies in the nucleus and restricted replication of chikungunya and Venezuelan equine encephalitis viruses. Although restriction by ISG20 was associated with inhibition of translation of infecting genomic RNA, degradation of viral RNAs was not observed. Instead, translation inhibition of viral RNA was associated with ISG20-induced upregulation of over 100 other genes, many of which encode known antiviral effectors. ISG20 modulated the production of IFIT1, an ISG that suppresses translation of alphavirus RNAs. Consistent with this observation, the pathogenicity of IFIT1-sensitive alphaviruses was increased inIsg20−/−mice compared to that of wild-type viruses but not in cells ectopically expressing ISG20. Our findings establish an indirect role for ISG20 in the early restriction of RNA virus replication by regulating expression of other ISGs that inhibit translation and possibly other activities in the replication cycle.IMPORTANCEThe host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased inIsg20−/−mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs.

scholarly journals Swine Interferon-Inducible Transmembrane Proteins Potently Inhibit Influenza A Virus Replication

2014 ◽  
Vol 89 (1) ◽  
pp. 863-869 ◽  
Author(s):  
Caroline Lanz ◽  
Emilio Yángüez ◽  
Dario Andenmatten ◽  
Silke Stertz
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Transmembrane Proteins ◽  
Human Interferon ◽  
Restriction Factors ◽  
Virus Inhibition ◽  
Antiviral Activities

Human interferon-inducible transmembrane proteins (IFITMs) were identified as restriction factors of influenza A virus (IAV). Given the important role of pigs in the zoonotic cycle of IAV, we cloned swine IFITMs (swIFITMs) and found two IFITM1-like proteins, one homologue of IFITM2, and a homologue of IFITM3. We show that swIFITM2 and swIFITM3 localize to endosomes and display potent antiviral activities. Knockdown of swIFITMs strongly reduced virus inhibition by interferon, establishing the swIFITMs as potent restriction factors in porcine cells.

scholarly journals Characterization of the Role of Host Cellular Factor Histone Deacetylase 10 during HIV-1 Replication

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 28
Author(s):  
Xiaozhuo Ran ◽  
Zhujun Ao ◽  
Titus Olukitibi ◽  
Xiaojian Yao
Keyword(s):  
Viral Replication ◽  
Histone Deacetylase ◽  
Catalytic Domain ◽  
Inhibitory Factor ◽  
Progeny Virus ◽  
Pcr Analysis ◽  
Transcriptional Level ◽  
Virus Infectivity ◽  
Hiv 1

To date, a series of histone deacetylases have been documented to restrict HIV-1 replication at different steps. In this study, we identified histone deacetylase 10 (HDAC10) as an inhibitory factor against HIV-1 replication. Our results showed that endogenous HDAC10 is downregulated at the transcriptional level during HIV-1 replication. By knocking down HDAC10 in CD4+ T cells with specific shRNAs, we observed that the downregulation of HDAC10 significantly facilitates viral replication. Moreover, RQ-PCR analysis revealed that the downregulation of HDAC10 increased viral integrated DNA. Further, we identified that HDAC10 interacts with the HIV-1 integrase (IN) and that the region of residues from 55 to 165 in the catalytic domain of IN is required for HDAC10 binding. Interestingly, we found that the interaction between HDAC10 and IN specifically decreases the interaction between IN and cellular protein lens epithelium-derived growth factor (LEDGF/p75), which consequently leads to the inhibition of viral integration. In addition, we have investigated the role of HDAC10 in the late stage of viral replication by detecting the infectiousness of progeny virus produced from HDAC10 knockdown cells or HDAC10 overexpressing cells and revealed that the progeny virus infectivity is increased in the HDAC10 downregulated cells, but decreased in the HDAC10 overexpressed cells. Overall, these findings provide evidence that HDAC10 acts as a cellular inhibitory factor at the early and late stages of HIV-1 replication.

scholarly journals Viral RNA is a target for Wolbachia-mediated pathogen blocking

2020 ◽  
Author(s):  
Tamanash Bhattacharya ◽  
Irene L.G. Newton ◽  
Richard W. Hardy
Keyword(s):  
Vector Control ◽  
Rna Viruses ◽  
Viral Rna ◽  
Host Association ◽  
Wolbachia Pipientis ◽  
Rapid Turnover ◽  
Virus Inhibition ◽  
Virus Dissemination ◽  
Mosquito Cells ◽  
Cellular Target

ABSTRACTThe ability of the endosymbiont Wolbachia pipientis to restrict RNA viruses is presently being leveraged to curb global transmission of arbovirus-induced diseases. Past studies have shown that virus replication is limited early in arthropod cells colonized by the bacterium, although it is unclear if this phenomenon is replicated in mosquito cells that first encounter viruses obtained through a vertebrate blood meal. Furthermore, these cellular events neither explain how Wolbachia limits dissemination of viruses between mosquito tissues, nor how it prevents transmission of infectious viruses from mosquitoes to vertebrate host. In this study, we try to address these issues using an array of mosquito cell culture models, with an additional goal being to identify a common viral target for pathogen blocking. Our results establish the viral RNA as a cellular target for Wolbachia- mediated inhibition, with the incoming viral RNA experiencing rapid turnover following internalization in cells. This early block in replication in mosquito cells initially infected by the virus thus consequently reduces the production of progeny viruses from these same cells. However, this is not the only contributor to pathogen blocking. We show that the presence of Wolbachia reduces the per-particle infectivity of progeny viruses on naïve mosquito and vertebrate cells, consequently limiting virus dissemination and transmission, respectively. Importantly, we demonstrate that this aspect of pathogen blocking is independent of any particular Wolbachia-host association and affects viruses belonging to Togaviridae and Flaviviridae families of RNA viruses. Finally, consistent with the idea of the viral RNA as a target, we find that the encapsidated virion RNA is less infectious for viruses produced from Wolbachia-colonized cells. Collectively, our findings present a common mechanism of pathogen blocking in mosquitoes that establish a link between virus inhibition in the cell to virus dissemination and transmission.AUTHORS SUMMARYViruses transmitted by arthropod vectors pose a significant global health risk. Incidence of diseases caused by these viruses can thus be reduced by implementing effective vector control strategies. This need is further exacerbated due to the lack of commercially available vaccines and antivirals. Presence of the intracellular bacteria Wolbachia pipientis is associated with virus inhibition in multiple mosquito vectors. Furthermore, Wolbachia is inherited transovarially and spreads across the vector population like a natural gene drive, making it an attractive vector control agent. In this study, we examine how the presence of the bacterium in arthropod cells prevents initial establishment of vertebrate cell derived viruses. Our results indicate rapid turnover of incoming viral RNA very early during infection in Wolbachia-colonized cells, thus establishing it as a cellular target for pathogen blocking. Additionally, upon evaluating how these events might further limit virus spread, we find that infectivity of progeny viruses belonging to multiple RNA virus families are reduced on a per-particle basis. This aspect of virus inhibition is independent of any particular Wolbachia-host association and affects how these viruses replicate in naïve mosquito and vertebrate cells, thus providing a collective basis of reduced virus dissemination and transmission in Wolbachia-colonized mosquitoes.

Role of autophagy in hepatitis C virus replication

2019 ◽  
Author(s):  
WI Twu ◽  
K Tabata ◽  
D Paul ◽  
R Bartenschlager
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Replication

scholarly journals RNA Helicase A Regulates the Replication of RNA Viruses

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 361
Author(s):  
Rui-Zhu Shi ◽  
Yuan-Qing Pan ◽  
Li Xing
Keyword(s):  
Virus Replication ◽  
Rna Binding ◽  
Rna Viruses ◽  
Rna Helicase ◽  
Rna Helicase A ◽  
Double Stranded Rna ◽  
Binding Domains ◽  
N Terminus

The RNA helicase A (RHA) is a member of DExH-box helicases and characterized by two double-stranded RNA binding domains at the N-terminus. RHA unwinds double-stranded RNA in vitro and is involved in RNA metabolisms in the cell. RHA is also hijacked by a variety of RNA viruses to facilitate virus replication. Herein, this review will provide an overview of the role of RHA in the replication of RNA viruses.

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