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Dom34 mediates targeting of exogenous RNA in the antiviral OAS/RNase L pathway.

ABSTRACT: The 2'-5'-oligoadenylate synthetase (OAS)/RNase L pathway is an innate immune system that protects hosts against pathogenic viruses and bacteria through cleavage of exogenous single-stranded RNA; however, this system's selective targeting mechanism remains unclear. Here, we identified an mRNA quality control factor Dom34 as a novel restriction factor for a positive-sense single-stranded RNA virus. Downregulation of Dom34 and RNase L increases viral replication, as well as half-life of the viral RNA. Dom34 directly binds RNase L to form a surveillance complex to recognize and eliminate the exogenous RNA in a manner dependent on translation. Interestingly, the feature detected by the surveillance complex is not the specific sequence of the viral RNA but the 'exogenous nature' of the RNA. We propose the following model for the selective targeting of exogenous RNA; OAS3 activated by the exogenous RNA releases 2'-5'-oligoadenylates (2-5A), which in turn converts latent RNase L to an active dimer. This accelerates formation of the Dom34-RNase L surveillance complex, and its selective localization to the ribosome on the exogenous RNA, thereby promoting degradation of the RNA. Our findings reveal that the selective targeting of exogenous RNA in antiviral defense occurs via a mechanism similar to that in the degradation of aberrant transcripts in RNA quality control.

SUBMITTER: Nogimori T

PROVIDER: S-EPMC6326797 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Dom34 mediates targeting of exogenous RNA in the antiviral OAS/RNase L pathway.

Nogimori Takuto T Nogimori Takuto T Nishiura Kyutatsu K Kawashima Sho S Nagai Takahiro T Oishi Yuka Y Hosoda Nao N Imataka Hiroaki H Kitamura Yoshiaki Y Kitade Yukio Y Hoshino Shin-Ichi SI

Nucleic acids research 20190101 1

The 2'-5'-oligoadenylate synthetase (OAS)/RNase L pathway is an innate immune system that protects hosts against pathogenic viruses and bacteria through cleavage of exogenous single-stranded RNA; however, this system's selective targeting mechanism remains unclear. Here, we identified an mRNA quality control factor Dom34 as a novel restriction factor for a positive-sense single-stranded RNA virus. Downregulation of Dom34 and RNase L increases viral replication, as well as half-life of the viral ...[more]

PMID: 30395302

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Project description:Arboviruses are pathogens of humans and animals. A better understanding of the interactions between these pathogens and the arthropod vectors, such as mosquitoes, that transmit them is necessary to develop novel control measures. A major antiviral pathway in the mosquito vector is the exogenous small interfering RNA (exo-siRNA) pathway, which is induced by arbovirus-derived double-stranded RNA in infected cells. Although recent work has shown the key role played by Argonaute-2 (Ago-2) and Dicer-2 (Dcr-2) in this pathway, the regulatory mechanisms that govern these pathways have not been studied in mosquitoes. Here, we show that the Domino ortholog p400 has antiviral activity against the alphavirus Semliki Forest virus (Togaviridae) both in Aedes aegypti-derived cells and in vivo Antiviral activity of p400 was also demonstrated against chikungunya virus (Togaviridae) and Bunyamwera virus (Peribunyaviridae) but not Zika virus (Flaviviridae). p400 was found to be expressed across mosquito tissues and regulated ago-2 but not dcr-2 transcript levels in A. aegypti mosquitoes. These findings provide novel insights into the regulation of an important aedine exo-siRNA pathway effector protein, Ago-2, by the Domino ortholog p400. They add functional insights to previous observations of this protein's antiviral and RNA interference regulatory activities in Drosophila melanogasterIMPORTANCE Female Aedes aegypti mosquitoes are vectors of human-infecting arthropod-borne viruses (arboviruses). In recent decades, the incidence of arthropod-borne viral infections has grown dramatically. Vector competence is influenced by many factors, including the mosquito's antiviral defenses. The exogenous small interfering RNA (siRNA) pathway is a major antiviral response restricting arboviruses in mosquitoes. While the roles of the effectors of this pathway, Argonaute-2 and Dicer-2 are well characterized, nothing is known about its regulation in mosquitoes. In this study, we demonstrate that A. aegypti p400, whose ortholog Domino in Drosophila melanogaster is a chromatin-remodeling ATPase member of the Tip60 complex, regulates siRNA pathway activity and controls ago-2 expression levels. In addition, we found p400 to have antiviral activity against different arboviruses. Therefore, our study provides new insights into the regulation of the antiviral response in A. aegypti mosquitoes.

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Dom34 mediates targeting of exogenous RNA in the antiviral OAS/RNase L pathway.

Publications

Dom34 mediates targeting of exogenous RNA in the antiviral OAS/RNase L pathway.

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