Characterization of RyDEN (C19orf66) as an Interferon-Stimulated Cellular Inhibitor against Dengue Virus Replication

Abstract

Dengue virus (DENV) is one of the most important arthropod-borne pathogens that cause life-threatening diseases in humans. However, no vaccine or specific antiviral is available for dengue. As seen in other RNA viruses, the innate immune system plays a key role in controlling DENV infection and disease outcome. Although the interferon (IFN) response, which is central to host protective immunity, has been reported to limit DENV replication, the molecular details of how DENV infection is modulated by IFN treatment are elusive. In this study, by employing a gain-of-function screen using a type I IFN-treated cell-derived cDNA library, we identified a previously uncharacterized gene, C19orf66, as an IFN-stimulated gene (ISG) that inhibits DENV replication, which we named Repressor of yield of DENV (RyDEN). Overexpression and gene knockdown experiments revealed that expression of RyDEN confers resistance to all serotypes of DENV in human cells. RyDEN expression also limited the replication of hepatitis C virus, Kunjin virus, Chikungunya virus, herpes simplex virus type 1, and human adenovirus. Importantly, RyDEN was considered to be a crucial effector molecule in the IFN-mediated anti-DENV response. When affinity purification-mass spectrometry analysis was performed, RyDEN was revealed to form a complex with cellular mRNA-binding proteins, poly(A)-binding protein cytoplasmic 1 (PABPC1), and La motif-related protein 1 (LARP1). Interestingly, PABPC1 and LARP1 were found to be positive modulators of DENV replication. Since RyDEN influenced intracellular events on DENV replication and, suppression of protein synthesis from DENV-based reporter construct RNA was also observed in RyDEN-expressing cells, our data suggest that RyDEN is likely to interfere with the translation of DENV via interaction with viral RNA and cellular mRNA-binding proteins, resulting in the inhibition of virus replication in infected cells.

C19ORF66 Broadly Escapes Virus-Induced Endonuclease Cleavage and Restricts Kaposi’s Sarcoma-Associated Herpesvirus

“…We thus proceeded to manually mine the literature to identify functions that might be important during viral infection. We were drawn to C19ORF66 (also known as RyDEN, IRAV, and SVA-1), as it was reported to be an antiviral interferon-stimulated gene (ISG) in the context of multiple viral infections (40,43,44). Furthermore, the transcript for C19ORF66 appeared in our comparative RNA-seq as the top escapee in all the replicates and with all the endonucleases tested.…”

“…Furthermore, C19ORF66 was found to interact with the NS3 protein of hepatitis C virus (53), localize to the replication complex of DENV (33), and occasionally colocalize in the cytoplasmic compartment with HIV-1 Rev and Tat proteins (40), pointing to a potential conserved role for C19ORF66 as a key player in the host-pathogen response. While it is still unclear how C19ORF66 participates in the regulation of these viruses, it was hypothesized that it may be mediated through its interaction with PABPC and LARP, two major RNA binding proteins (43). PABPC and LARP were recently shown to be relocated upon SOX-induced widespread RNA decay and to be linked to the transcription feedback loop that occurs during host shutoff (46).…”

“…C19ORF66 (also annotated RyDEN, IRAV, and SVA-1) is an interferon-stimulated gene (ISG) that has been found to be upregulated upon infection by a number a viruses (35)(36)(37)(38)(39)(40), including herpesviruses (41,42), in several large-scale screens. Recently, C19ORF66 was demonstrated to repress dengue virus (DENV) replication and gene expression by interacting with the cytoplasmic poly(A) binding protein, PABPC (43), and the RNA helicase MOV10 (44), suggesting that C19ORF66 may restrict DENV infection by directly influencing the host gene expression machinery and/or directly targeting viral RNA for degradation, making it an intriguing candidate dominant escapee during KSHV infection.…”

Coordination of transcriptional and translational regulations in human epithelial cells infected by Listeria monocytogenes

“…Previous reports however support the existence of potent regulations affecting host mRNA translation during bacterial infections. For instance, a growing number of studies have finely characterised miRNA-mediated regulation 5 of specific host transcripts and cellular processes (Aguilar, Mano, & Eulalio, 2019;reviewed in Duval, Cossart, & Lebreton, 2017). Pathogenic bacteria can also target central host translation mechanisms, and thereby tune -positively or negatively-the production of host defence proteins (reviewed in Mohr & Sonenberg, 2012).…”

“…In the present study, we aimed at clarifying the respective contribution of transcriptional and translational regulations on the reshaping of host gene expression of a human epithelial cell line, over a 10-h time course of infection with an epidemic isolate of Lm. Using ribosome profiling (Ingolia,Hussmann,& 5 Weissman, 2018), we mapped with high resolution the host translatome during infection, compared it with transcriptome data, and grouped genes that were under transcriptional and/or translational control according to their regulation profiles with regards to time. Our results revealed a dominant pattern, where the rapid induction of gene expression was mainly driven by transcriptional regulation and affected inflammationrelated genes, whereas most repressive events were translational, and affected genes encoding components of 10 the translation machinery.…”