scholarly journals Bombyx mori nucleopolyhedrovirus BM5 protein regulates progeny virus production and viral gene expression

Virology ◽  
2016 ◽  
Vol 498 ◽  
pp. 240-249 ◽  
Author(s):  
Ryuhei Kokusho ◽  
Yoshikazu Koh ◽  
Masaru Fujimoto ◽  
Toru Shimada ◽  
Susumu Katsuma
Keyword(s):  
Gene Expression ◽  
Bombyx Mori ◽  
Virus Production ◽  
Viral Gene Expression ◽  
Progeny Virus ◽  
Viral Gene ◽  
Bombyx Mori Nucleopolyhedrovirus ◽  
Progeny Virus Production

scholarly journals Murine Cytomegalovirus Protein pM91 Interacts with pM79 and Is Critical for Viral Late Gene Expression

2018 ◽  
Vol 92 (18) ◽  
Author(s):  
Deng Pan ◽  
Tian Han ◽  
Shubing Tang ◽  
Wenjia Xu ◽  
Qunchao Bao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Replication ◽  
Gene Transcription ◽  
Virus Production ◽  
Progeny Virus ◽  
Late Gene ◽  
Cmv Infection ◽  
Late Gene Expression ◽  
Viral Dna ◽  
Progeny Virus Production

ABSTRACTViral gene expression is tightly regulated during cytomegalovirus (CMV) lytic replication, but the detailed mechanism of late gene transcription remains to be fully understood. Previous studies reported that six viral proteins (named viral transactivation factors [vTFs]) supporting late gene expression were conserved in beta- and gammaherpesviruses but not in alphaherpesviruses. Here, we performed coimmunoprecipitation experiments to elucidate the organization of these six proteins in murine CMV. Our results showed that these proteins formed a complex by both direct and indirect interactions. Specifically, pM91 strongly bound to pM79 even in the absence of other vTFs. Similar to pM79, pM91 exhibited early-late expression kinetics and localized within nuclear viral replication compartments during infection. Functional analysis was also performed using the pM91-deficient virus. Real-time PCR results revealed that abrogation of M91 expression markedly reduced viral late gene expression and progeny virus production without affecting viral DNA synthesis. Using mutagenesis, we found that residues E61, D62, D89, and D96 in pM91 were required for the pM91-pM79 interaction. Disruption of the interaction via E61A/D62A or D89A/D96A double mutation in the context of virus infection inhibited progeny virus production. Our data indicate that pM91 is a component of the viral late gene transcription factor complex and that the pM91-pM79 interaction is essential for viral late gene expression.IMPORTANCECytomegalovirus (CMV) infection is the leading cause of birth defects and causes morbidity and mortality in immunocompromised patients. The regulation of viral late gene transcription is not well elucidated, and understanding of this process benefits the development of novel therapeutics against CMV infection. This study (i) identified that six viral transactivation factors encoded by murine CMV form a complex, (ii) demonstrated that pM91 interacts with pM79 and that pM91 and pM79 colocalize in the nuclear viral replication compartments, (iii) confirmed that pM91 is critical for viral late gene expression but dispensable for viral DNA replication, and (iv) revealed that the pM91-pM79 interaction is required for progeny virus production. These findings give an explanation of how CMV regulates late gene expression and have important implications for the design of antiviral strategies.

scholarly journals Adenovirus Virus-Associated RNA Is Processed to Functional Interfering RNAs Involved in Virus Production

2006 ◽  
Vol 80 (3) ◽  
pp. 1376-1384 ◽  
Author(s):  
Oscar Aparicio ◽  
Nerea Razquin ◽  
Mikel Zaratiegui ◽  
Iñigo Narvaiza ◽  
Puri Fortes
Keyword(s):  
Gene Expression ◽  
Virus Production ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Small Interfering Rnas ◽  
Control Of Gene Expression ◽  
Posttranscriptional Gene Silencing ◽  
Argonaute 2 ◽  
Complementary Sequences ◽  
Infected Cells

ABSTRACT Posttranscriptional gene silencing allows sequence-specific control of gene expression. Specificity is guaranteed by small antisense RNAs such as microRNAs (miRNAs) or small interfering RNAs (siRNAs). Functional miRNAs derive from longer double-stranded RNA (dsRNA) molecules that are cleaved to pre-miRNAs in the nucleus and are transported by exportin 5 (Exp 5) to the cytoplasm. Adenovirus-infected cells express virus-associated (VA) RNAs, which are dsRNA molecules similar in structure to pre-miRNAs. VA RNAs are also transported by Exp 5 to the cytoplasm, where they accumulate. Here we show that small RNAs derived from VA RNAs (svaRNAs), similar to miRNAs, can be found in adenovirus-infected cells. VA RNA processing to svaRNAs requires neither viral replication nor viral protein expression, as evidenced by the fact that svaRNA accumulation can be detected in cells transfected with VA sequences. svaRNAs are efficiently bound by Argonaute 2, the endonuclease of the RNA-induced silencing complex, and behave as functional siRNAs, in that they inhibit the expression of reporter genes with complementary sequences. Blocking svaRNA-mediated inhibition affects efficient adenovirus production, indicating that svaRNAs are required for virus viability. Thus, svaRNA-mediated silencing could represent a novel mechanism used by adenoviruses to control cellular or viral gene expression.

scholarly journals HCMV miRNA Targets Reveal Important Cellular Pathways for Viral Replication, Latency, and Reactivation

2018 ◽  
Vol 4 (4) ◽  
pp. 29 ◽  
Author(s):  
Nicole Diggins ◽  
Meaghan Hancock
Keyword(s):  
Gene Expression ◽  
Latent Infection ◽  
Current Knowledge ◽  
Critical Role ◽  
Viral Gene Expression ◽  
Lytic Replication ◽  
Progeny Virus ◽  
Viral Gene ◽  
Cellular Targets ◽  
Differentiated Cells

It is now well appreciated that microRNAs (miRNAs) play a critical role in the lifecycles of many herpes viruses. The human cytomegalovirus (HCMV) replication cycle varies significantly depending on the cell type infected, with lytic replication occurring in fully-differentiated cells such as fibroblasts, endothelial cells, or macrophages, and latent infection occurring in less-differentiated CD14+ monocytes and CD34+ hematopoietic progenitor cells where viral gene expression is severely diminished and progeny virus is not produced. Given their non-immunogenic nature and their capacity to target numerous cellular and viral transcripts, miRNAs represent a particularly advantageous means for HCMV to manipulate viral gene expression and cellular signaling pathways during lytic and latent infection. This review will focus on our current knowledge of HCMV miRNA viral and cellular targets, and discuss their importance in lytic and latent infection, highlight the challenges of studying HCMV miRNAs, and describe how viral miRNAs can help us to better understand the cellular processes involved in HCMV latency.

scholarly journals IP-10 and CXCR3 signaling inhibit Zika virus replication in human prostate cells

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244587
Author(s):  
Jennifer L. Spencer Clinton ◽  
Linda L. Tran ◽  
Megan B. Vogt ◽  
David R. Rowley ◽  
Jason T. Kimata ◽  
...  
Keyword(s):  
Gene Expression ◽  
Zika Virus ◽  
Sexual Transmission ◽  
Virus Transmission ◽  
Virus Production ◽  
Viral Gene Expression ◽  
Human Prostate ◽  
Viral Gene ◽  
Prostate Cells ◽  
Cxcr3 Signaling

Our previous studies have shown that Zika virus (ZIKV) replicates in human prostate cells, suggesting that the prostate may serve as a long-term reservoir for virus transmission. Here, we demonstrated that the innate immune responses generated to three distinct ZIKV strains (all isolated from human serum) were significantly different and dependent on their passage history (in mosquito, monkey, or human cells). In addition, some of these phenotypic differences were reduced by a single additional cell culture passage, suggesting that viruses that have been passaged more than 3 times from the patient sample will no longer reflect natural phenotypes. Two of the ZIKV strains analyzed induced high levels of the IP-10 chemokine and IFNγ in human prostate epithelial and stromal mesenchymal stem cells. To further understand the importance of these innate responses on ZIKV replication, we measured the effects of IP-10 and its downstream receptor, CXCR3, on RNA and virus production in prostate cells. Treatment with IP-10, CXCR3 agonist, or CXCR3 antagonist significantly altered ZIKV viral gene expression, depending on their passage in cells of relevant hosts (mosquito or human). We detected differences in gene expression of two primary CXCR3 isoforms (CXCR3-A and CXCR3-B) on the two cell types, possibly explaining differences in viral output. Lastly, we examined the effects of IP-10, agonist, or antagonist on cell death and proliferation under physiologically relevant infection rates, and detected no significant differences. Although we did not measure protein expression directly, our results indicate that CXCR3 signaling may be a target for therapeutics, to ultimately stop sexual transmission of this virus.

scholarly journals Latency Reversing Agents: Kick and Kill of HTLV-1?

2021 ◽  
Vol 22 (11) ◽  
pp. 5545
Author(s):  
Annika P. Schnell ◽  
Stephan Kohrt ◽  
Andrea K. Thoma-Kress
Keyword(s):  
Gene Expression ◽  
T Cell ◽  
Viral Gene Expression ◽  
Cytotoxic T Cell ◽  
Viral Gene ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Reversing Agents ◽  
Ctl Responses

Human T-cell leukemia virus type 1 (HTLV-1), the cause of adult T-cell leukemia/lymphoma (ATLL), is a retrovirus, which integrates into the host genome and persistently infects CD4+ T-cells. Virus propagation is stimulated by (1) clonal expansion of infected cells and (2) de novo infection. Viral gene expression is induced by the transactivator protein Tax, which recruits host factors like positive transcription elongation factor b (P-TEFb) to the viral promoter. Since HTLV-1 gene expression is repressed in vivo by viral, cellular, and epigenetic mechanisms in late phases of infection, HTLV-1 avoids an efficient CD8+ cytotoxic T-cell (CTL) response directed against the immunodominant viral Tax antigen. Hence, therapeutic strategies using latency reversing agents (LRAs) sought to transiently activate viral gene expression and antigen presentation of Tax to enhance CTL responses towards HTLV-1, and thus, to expose the latent HTLV-1 reservoir to immune destruction. Here, we review strategies that aimed at enhancing Tax expression and Tax-specific CTL responses to interfere with HTLV-1 latency. Further, we provide an overview of LRAs including (1) histone deacetylase inhibitors (HDACi) and (2) activators of P-TEFb, that have mainly been studied in context of human immunodeficiency virus (HIV), but which may also be powerful in the context of HTLV-1.

scholarly journals The [KIL-d] Element Specifically Regulates Viral Gene Expression in Yeast

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 601-609 ◽  
Author(s):  
Zsolt Tallóczy ◽  
Rebecca Mazar ◽  
Denise E Georgopoulos ◽  
Fausto Ramos ◽  
Michael J Leibowitz
Keyword(s):  
Gene Expression ◽  
Phenotypic Expression ◽  
Viral Gene Expression ◽  
Virus Genome ◽  
Viral Rna ◽  
High Rate ◽  
Viral Gene ◽  
Double Stranded Rna ◽  
Yeast Prions ◽  
Killer Virus

Abstract The cytoplasmically inherited [KIL-d] element epigenetically regulates killer virus gene expression in Saccharomyces cerevisiae. [KIL-d] results in variegated defects in expression of the M double-stranded RNA viral segment in haploid cells that are “healed” in diploids. We report that the [KIL-d] element is spontaneously lost with a frequency of 10−4–10−5 and reappears with variegated phenotypic expression with a frequency of ≥10−3. This high rate of loss and higher rate of reappearance is unlike any known nucleic acid replicon but resembles the behavior of yeast prions. However, [KIL-d] is distinct from the known yeast prions in its relative guanidinium hydrochloride incurability and independence of Hsp104 protein for its maintenance. Despite its transmissibility by successive cytoplasmic transfers, multiple cytoplasmic nucleic acids have been proven not to carry the [KIL-d] trait. [KIL-d] epigenetically regulates the expression of the M double-stranded RNA satellite virus genome, but fails to alter the expression of M cDNA. This specificity remained even after a cycle of mating and meiosis. Due to its unique genetic properties and viral RNA specificity, [KIL-d] represents a new type of genetic element that interacts with a viral RNA genome.

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