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Mechanistic insights into the inhibition of stress granule formation by a viral protein Sadasivan, Jibin
Abstract
Stress granules (SG) are ribonucleoprotein aggregates that accumulate during cellular stress when translation is limited. Inhibition of SG assembly has been observed under virus infection across species, suggesting a conserved fundamental viral strategy. However, the significance of SG modulation during virus infection is not fully understood. The 1A protein encoded by the model dicistrovirus, Cricket Paralysis Virus (CrPV), is a multifunctional viral protein that can inhibit SG formation and bind to and degrade Argonaute-2 (Ago-2) in an E3 ubiquitin ligase-dependent manner to block the antiviral RNA interference pathway. Moreover, the R146 residue at the C-terminus of 1A is necessary for virus infection in Drosophila S2 cells and flies. Here, I uncouple CrPV-1A's functions and provide insights into its underlying mechanism for SG inhibition. CrPV-1A’s ability to inhibit SG formation does not require the Ago-2 binding domain but does require the E3 ubiquitin ligase binding domain. Overexpression and infection studies in Drosophila and human cells showed that wild-type CrPV-1A but not mutant R146A CrPV-1A localizes to the nuclear membrane, which correlates with nuclear enrichment of poly(A)+ RNA. Transcriptome analysis demonstrated that a single R146A mutation dramatically dampens host transcriptome changes in CrPV-infected cells. Finally, inhibition of SG formation by CrPV-1A requires Ranbp2/Nup358 in an R146-dependent manner. I propose that CrPV utilizes a multifaceted strategy for productive virus infection whereby the CrPV-1A protein interferes with a nuclear event that contributes to the suppression of SG assembly.
Item Metadata
Title |
Mechanistic insights into the inhibition of stress granule formation by a viral protein
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Creator | |
Supervisor | |
Publisher |
University of British Columbia
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Date Issued |
2022
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Description |
Stress granules (SG) are ribonucleoprotein aggregates that accumulate during cellular stress when translation is limited. Inhibition of SG assembly has been observed under virus infection across species, suggesting a conserved fundamental viral strategy. However, the significance of SG modulation during virus infection is not fully understood. The 1A protein encoded by the model dicistrovirus, Cricket Paralysis Virus (CrPV), is a multifunctional viral protein that can inhibit SG formation and bind to and degrade Argonaute-2 (Ago-2) in an E3 ubiquitin ligase-dependent manner to block the antiviral RNA interference pathway. Moreover, the R146 residue at the C-terminus of 1A is necessary for virus infection in Drosophila S2 cells and flies. Here, I uncouple CrPV-1A's functions and provide insights into its underlying mechanism for SG inhibition. CrPV-1A’s ability to inhibit SG formation does not require the Ago-2 binding domain but does require the E3 ubiquitin ligase binding domain. Overexpression and infection studies in Drosophila and human cells showed that wild-type CrPV-1A but not mutant R146A CrPV-1A localizes to the nuclear membrane, which correlates with nuclear enrichment of poly(A)+ RNA. Transcriptome analysis demonstrated that a single R146A mutation dramatically dampens host transcriptome changes in CrPV-infected cells. Finally, inhibition of SG formation by CrPV-1A requires Ranbp2/Nup358 in an R146-dependent manner. I propose that CrPV utilizes a multifaceted strategy for productive virus infection whereby the CrPV-1A protein interferes with a nuclear event that contributes to the suppression of SG assembly.
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Genre | |
Type | |
Language |
eng
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Date Available |
2022-10-18
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Provider |
Vancouver : University of British Columbia Library
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Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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DOI |
10.14288/1.0421301
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2022-11
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Campus | |
Scholarly Level |
Graduate
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Rights URI | |
Aggregated Source Repository |
DSpace
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Rights
Attribution-NonCommercial-NoDerivatives 4.0 International