The helicase domain of human Dicer prevents RNAi-independent activation of antiviral and inflammatory pathways
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PROVIDER: PRJNA1010105 | ENA |
REPOSITORIES: ENA
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Project description:In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1-expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
2024-01-26 | GSE241798 | GEO
Project description:In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1-expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
2024-01-26 | GSE241797 | GEO
Project description:In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1-expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
2024-01-26 | GSE241796 | GEO
Project description:The helicase domain of human Dicer prevents RNAi-independent activation of antiviral and inflammatory pathways
| PRJNA1010104 | ENA
Project description:The helicase domain of human Dicer prevents RNAi-independent activation of antiviral and inflammatory pathways
| PRJNA1010106 | ENA
Project description:In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1 expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
| S-EPMC10907635 | biostudies-literature
Project description:In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1-expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
| S-SCDT-10_1038-S44318-024-00035-2 | biostudies-other
Project description:The innate immune response against viruses mainly involves type I interferon (IFN) in mammalian cells. The exact contribution of the RNA silencing machinery remains to be established, but several recent studies indicate that the type III ribonuclease DICER can generate viral siRNAs in specific conditions. In addition, it has been proposed that type I IFN and RNA silencing could be mutually exclusive responses. In order to decipher the implication of DICER during infection of human cells with the Sindbis virus, we determined its interactome by immunoprecipitation and mass spectrometry analysis. Our results show that human DICER specifically interacts with several double-stranded RNA binding proteins and helicases during viral infection. In particular, proteins such as DHX9, ADAR-1 and the protein kinase PKR are enriched with DICER in virus-infected cells. We validated the importance of the helicase domain of DICER in its interaction with PKR and showed that it has functional consequences for the cellular response to viral infection.
2021-04-15 | PXD019093 | Pride
Project description:Ribonuclease Dicer generates small RNAs for RNA interference (RNAi) and microRNA (miRNA) pathways. Mammalian Dicer produces miRNAs but its tripartite N-terminal helicase domain inhibits processing of double-stranded RNA for RNAi. Mouse oocytes express Dicer, which enhances RNAi because it lacks the helicase’s proximal subdomain HEL1. Here we show that genetic removal of HEL1 in mice causes embryonic growth retardation, defects in the cardiopulmonary system, and perinatal lethality. HEL1 suppresses biogenesis of mirtrons, a non-canonical low-abundant class of miRNAs, and is required for high-fidelity cleavage and strand selection during biogenesis of canonical miRNAs. Essential is the HEL1 structure, not its helicase activity, because mutations of critical aminoacids do not affect viability or fertility and have minimal impact on miRNA biogenesis. Altogether, HEL1 is a critical structural component of Dicer in its role of a highly conserved structural “mold” that ensures high-fidelity processing and adaptive evolution of mammalian miRNA precursors.
2024-04-10 | GSE243016 | GEO
Project description:RNA interference (RNAi) is a cell-intrinsic antiviral defense conserved in diverse organisms. However, the mechanism by which mammalian antiviral RNAi is regulated is largely unknown. Herein, we uncover that STUB1, an E3 ubiquitin ligase, interacts with and ubiquitinates AGO2, the core component of RNAi pathway, resulting in the degradation of AGO2 via ubiquitin-proteasome system. Additionally, STUB1 can induce the degradation of the other mammalian AGO proteins including AGO1, AGO3, and AGO4. Our further study reveals that STUB1 also interacts with and mediates the ubiquitination of Dicer, the endoribonuclease responsible for siRNA or miRNA biogenesis, via K48-linked poly-ubiquitin, which induces the degradation of Dicer and its specialized form, termed antiviral Dicer (aviDicer) that usually expresses in stem cells. Loss of STUB1 upregulated Dicer and AGO2, thereby enhancing antiviral RNAi to effectively inhibit viral RNA replication in mammalian cells. In vivo, the STUB1 deficiency markedly enhanced the production of virus-derived siRNAs and elicited a potent antiviral effect against Enterovirus-A71 (EV-A71) infection in newborn mouse. Our findings demonstrate STUB1 as a novel negative regulator of RNAi by mediating the ubiquitination and degradation of Dicer and AGO proteins, and provide novel insights into the regulatory mechanism of antiviral RNAi in mammals.
2021-11-22 | GSE189203 | GEO