Sindbis virus infectivity improves during the course of infection in both mammalian and mosquito cells

Sokoloski, Kevin J.; Hayes, Chelsea; Dunn, Megan P.; Balke, Jennifer L.; Hardy, Richard W.; Mukhopadhyay, Suchetana

doi:10.1016/j.virusres.2012.03.015

Cited by 28 publications

(55 citation statements)

References 22 publications

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“…At first glance, these findings appear to be contradictory to the RNA half-lives previously reported for the alphavirus RNA species; however, a fundamental difference between the two studies exists (23,28). This study evaluated the half-lives of the incoming viral genomic RNA immediately after viral infection, whereas the previous studies evaluated viral RNA stability later during infection.…”

Section: Discussionmentioning

confidence: 74%

“…Nonetheless, when during viral replication the synthesis of noncapped viral genomic RNAs occurs and to what levels they accumulate were unclear. We have previously reported that the infectivity of SINV, as measured by the ratio of particles to infectious units, improves with time in tissue culture systems (23). Since the ratios of noncapped to 7me GpppA-capped SINV genomic RNAs were highly similar to the ratios of particles to infectious units observed for mammalian-cell-and mosquito cellderived SINV particles, we hypothesized that the number of noncapped particles (viral particles that contain a noncapped genomic RNA) would decrease, while the number of 7me GpppA-capped particles would increase, with time.…”

Section: Resultsmentioning

confidence: 99%

“…Viral titer determination was performed by using standard plaque assays on BHK-21 cells. Quantitative assessment of the particle numbers of viral samples was performed as previously described (23,26). Briefly, viral samples (100 l) were treated with 10 g of RNase A for 15 min at 37°C prior to extraction with TRIzol reagent.…”

Section: Methodsmentioning

confidence: 99%

“…The viral type 0 cap structure differs from the cellular type I 7me Gppp 2me G structure in its lack of a second methylation event. We have reported previously that the infectivity of a model alphavirus, Sindbis virus (SINV), as measured by the ratio of particles to infectious units, was dependent primarily on the deriving host cell and generally improved with respect to time (23). Additionally, SINV particles produced from mosquito cells were more efficient, in terms of infectivity, than mammalian-cell-derived viral particles.…”

mentioning

confidence: 99%

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Noncapped Alphavirus Genomic RNAs and Their Role during Infection

Sokoloski

Haist

Morrison

et al. 2015

J Virol

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Alphaviruses are enveloped positive-sense RNA viruses that exhibit a wide host range consisting of vertebrate and invertebrate species. Previously we have reported that the infectivity of Sindbis virus (SINV), the model alphavirus, was largely a function of the cell line producing the viral particles. Mammalian-cell-derived SINV particles, on average, exhibit a higher particle-to-PFU ratio than mosquito cell-derived SINV particles. Nevertheless, the outcome of nonproductive infection, the molecular traits that determine particle infectivity and the biological importance of noninfectious particles were, prior to this study, unknown. Here, we report that the incoming genomic RNAs of noninfectious SINV particles undergo rapid degradation following infection. Moreover, these studies have led to the identification of the absence of the 5= cap structure as a primary molecular determinant of particle infectivity. We show that the genomic RNAs of alphaviruses are not universally 5= capped, with a significant number of noncapped genomic RNA produced early in infection. The production of noncapped viral genomic RNAs is important to the establishment and maintenance of alphaviral infection. IMPORTANCEThis report is of importance to the field of virology for three reasons. First, these studies demonstrate that noncapped Sindbis virus particles are produced as a result of viral RNA synthesis. Second, this report is, to our knowledge, the first instance of the direct measurement of the half-life of an incoming genomic RNA from a positive-sense RNA virus. Third, these studies indicate that alphaviral infection is likely a concerted effort of infectious and noninfectious viral particles.A lphaviruses are enveloped, positive-sense RNA viruses that are cyclically transmitted between sylvatic vertebrate reservoir hosts and a mosquito vector during the enzootic cycle. The maintenance of this cyclical transmission is vital to viral fitness, as prolonged serial passage within a single host results in attenuation in the alternate host (1-4). Moreover, the ultimate outcome of alphaviral infection differs between vertebrate and invertebrate hosts, as infection of a vertebrate host results in acute cytolytic infection whereas infection of invertebrate hosts often results in persistent infection with minimal cell death (5-11). The widespread geographic distribution of competent vector mosquito species leading to contact with immunologically naive human populations has resulted in several significant outbreaks of alphaviral disease (12)(13)(14). Perhaps most notable is the ongoing reemergence of chikungunya virus, which caused significant morbidity during the height of the 2006 epidemic, with as many as 40,000 new cases per week (13).Despite the range of diseases and morbidity associated within the genus, the underlying molecular life cycles are highly similar in the two hosts. Since alphaviruses are positive-sense RNA viruses, they function similarly to cellular mRNAs, relying on the translation of the incoming viral genome to ini...

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Section: Discussionmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Noncapped Alphavirus Genomic RNAs and Their Role during Infection

Sokoloski

Haist

Morrison

et al. 2015

J Virol

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“…At the end of the VNP assembly procedure we obtained 1 × 10 3 infectious VNPs. Using 100 as the ratio of total particles to infectious particles, 58 we calculated Figure 5. VNP containing Au-nanoparticle enters BHK cells.…”

Section: ■ Discussionmentioning

confidence: 99%

The Packaging of Different Cargo into Enveloped Viral Nanoparticles

Fan

Tsvetkova²,

Khuong³

et al. 2012

Mol. Pharmaceutics

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Viral nanoparticles used for biomedical applications must be able to discriminate between tumor or virus-infected host cells and healthy host cells. In addition, viral nanoparticles must have the flexibility to incorporate a wide range of cargo, from inorganic metals to mRNAs to small molecules. Alphaviruses are a family of enveloped viruses for which some species are intrinsically capable of systemic tumor targeting. Alphavirus virus-like particles, or viral nanoparticles, can be generated from in vitro self-assembled core-like particles using nonviral nucleic acid. In this work, we expand on the types of cargo that can be incorporated into alphavirus core-like particles and the molecular requirements for packaging this cargo. We demonstrate that different core-like particle templates can be further enveloped to form viral nanoparticles that are capable of cell entry. We propose that alphaviruses can be selectively modified to create viral nanoparticles for biomedical applications and basic research.

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Role for subgenomic mRNA in host translation inhibition during Sindbis virus infection of mammalian cells

Patel¹,

Burnham²,

Gebhart³

et al. 2013

Virology

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Sindbis virus subgenomic mRNA is efficiently translated in infected vertebrate cells whereas host translation is shut-off. Deletions in the 5′ UTR of the subgenomic mRNA were made to investigate its role in viral gene expression. Deletion of nucleotides 1-10 and 11-20 caused a small plaque phenotype, reduced levels of subgenomic mRNA and structural proteins, and increased expression of nonstructural proteins. Whereas deletion 1-10 virus inhibited cellular protein synthesis, deletion 11-20 did so inefficiently. A large plaque revertant of deletion 11-20, possessing a duplication of the subgenomic promoter region, produced subgenomic mRNA at WT levels and restored inhibition of host protein synthesis. Further analysis of the mutant and revertant 5′UTR sequences showed the ability to shut-off host cell translation correlated with the efficiency of translation of subgenomic mRNA. We propose that the translational efficiency and quantity of the subgenomic mRNA play a role in inhibition of host cell translation.

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Sindbis virus infectivity improves during the course of infection in both mammalian and mosquito cells

Cited by 28 publications

References 22 publications

Noncapped Alphavirus Genomic RNAs and Their Role during Infection

Noncapped Alphavirus Genomic RNAs and Their Role during Infection

The Packaging of Different Cargo into Enveloped Viral Nanoparticles

Role for subgenomic mRNA in host translation inhibition during Sindbis virus infection of mammalian cells

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