Troupin A, Londono-Renteria B, Conway MJ, Cloherty E, Jameson S, Higgs S, Vanlandingham DL, Fikrig E, Colpitts TM. A novel mosquito ubiquitin targets viral envelope protein for degradation and reduces virion production during dengue virus infection.
Biochim Biophys Acta Gen Subj 2016;
1860:1898-909. [PMID:
27241849 PMCID:
PMC4949077 DOI:
10.1016/j.bbagen.2016.05.033]
[Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/27/2016] [Accepted: 05/26/2016] [Indexed: 11/17/2022]
Abstract
Background
Dengue virus (DENV) is a mosquito-borne flavivirus that causes significant human disease and mortality in the tropics and subtropics. By examining the effects of virus infection on gene expression, and interactions between virus and vector, new targets for prevention of infection and novel treatments may be identified in mosquitoes. We previously performed a microarray analysis of the Aedes aegypti transcriptome during infection with DENV and found that mosquito ubiquitin protein Ub3881 (AAEL003881) was specifically and highly down-regulated. Ubiquitin proteins have multiple functions in insects, including marking proteins for proteasomal degradation, regulating apoptosis and mediating innate immune signaling.
Methods
We used qRT-PCR to quantify gene expression and infection, and RNAi to reduce Ub3881 expression. Mosquitoes were infected with DENV through blood feeding. We transfected DENV protein expression constructs to examine the effect of Ub3881 on protein degradation. We used site-directed mutagenesis and transfection to determine what amino acids are involved in Ub3881-mediated protein degradation. Immunofluorescence, Co-immunoprecipitation and Western blotting were used to examine protein interactions and co-localization.
Results
The overexpression of Ub3881, but not related ubiquitin proteins, decreased DENV infection in mosquito cells and live Ae. aegypti. The Ub3881 protein was demonstrated to be involved in DENV envelope protein degradation and reduce the number of infectious virions released.
Conclusions
We conclude that Ub3881 has several antiviral functions in the mosquito, including specific viral protein degradation.
General significance
Our data highlights Ub3881 as a target for future DENV prevention strategies in the mosquito transmission vector.
A novel mosquito ubiquitin, Ub3881, is identified in Aedes aegypti.
Ub3881 is shown to have antiviral functions during dengue virus infection of the mosquito.
Ub3881 targets a dengue viral protein for degradation during infection.
Future dengue virus prevention strategies could incorporate Ub3881 as a target to prevent mosquito infection.
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