TY - JOUR
T1 - IFIT1 Differentially Interferes with Translation and Replication of Alphavirus Genomes and Promotes Induction of Type I Interferon
AU - Reynaud, Josephine M.
AU - Kim, Dal Young
AU - Atasheva, Svetlana
AU - Rasalouskaya, Aliaksandra
AU - White, James P.
AU - Diamond, Michael S.
AU - Weaver, Scott C.
AU - Frolova, Elena I.
AU - Frolov, Ilya
N1 - Publisher Copyright:
© 2015 Reynaud et al.
PY - 2015/4/1
Y1 - 2015/4/1
N2 - Alphaviruses are a group of widely distributed human and animal pathogens. It is well established that their replication is sensitive to type I IFN treatment, but the mechanism of IFN inhibitory function remains poorly understood. Using a new experimental system, we demonstrate that in the presence of IFN-β, activation of interferon-stimulated genes (ISGs) does not interfere with either attachment of alphavirus virions to the cells, or their entry and nucleocapsid disassembly. However, it strongly affects translation of the virion-delivered virus-specific RNAs. One of the ISG products, IFIT1 protein, plays a major role in this translation block, although an IFIT1-independent mechanism is also involved. The 5’UTRs of the alphavirus genomes were found to differ significantly in their ability to drive translation in the presence of increased concentration of IFIT1. Prior studies have shown that adaptation of naturally circulating alphaviruses to replication in tissue culture results in accumulation of mutations in the 5’UTR, which increase the efficiency of the promoter located in the 5’end of the genome. Here, we show that these mutations also decrease resistance of viral RNA to IFIT1-induced translation inhibition. In the presence of higher levels of IFIT1, alphaviruses with wt 5’UTRs became potent inducers of type I IFN, suggesting a new mechanism of type I IFN induction. We applied this knowledge of IFIT1 interaction with alphaviruses to develop new attenuated variants of Venezuelan equine encephalitis and chikungunya viruses that are more sensitive to the antiviral effects of IFIT1, and thus could serve as novel vaccine candidates.
AB - Alphaviruses are a group of widely distributed human and animal pathogens. It is well established that their replication is sensitive to type I IFN treatment, but the mechanism of IFN inhibitory function remains poorly understood. Using a new experimental system, we demonstrate that in the presence of IFN-β, activation of interferon-stimulated genes (ISGs) does not interfere with either attachment of alphavirus virions to the cells, or their entry and nucleocapsid disassembly. However, it strongly affects translation of the virion-delivered virus-specific RNAs. One of the ISG products, IFIT1 protein, plays a major role in this translation block, although an IFIT1-independent mechanism is also involved. The 5’UTRs of the alphavirus genomes were found to differ significantly in their ability to drive translation in the presence of increased concentration of IFIT1. Prior studies have shown that adaptation of naturally circulating alphaviruses to replication in tissue culture results in accumulation of mutations in the 5’UTR, which increase the efficiency of the promoter located in the 5’end of the genome. Here, we show that these mutations also decrease resistance of viral RNA to IFIT1-induced translation inhibition. In the presence of higher levels of IFIT1, alphaviruses with wt 5’UTRs became potent inducers of type I IFN, suggesting a new mechanism of type I IFN induction. We applied this knowledge of IFIT1 interaction with alphaviruses to develop new attenuated variants of Venezuelan equine encephalitis and chikungunya viruses that are more sensitive to the antiviral effects of IFIT1, and thus could serve as novel vaccine candidates.
UR - http://www.scopus.com/inward/record.url?scp=84929494303&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84929494303&partnerID=8YFLogxK
U2 - 10.1371/journal.ppat.1004863
DO - 10.1371/journal.ppat.1004863
M3 - Article
C2 - 25927359
AN - SCOPUS:84929494303
SN - 1553-7366
VL - 11
JO - PLoS pathogens
JF - PLoS pathogens
IS - 4
M1 - e1004863
ER -