DExD/H Box Helicases DDX24 and DDX49 Inhibit Reactivation of Kaposi's Sarcoma Associated Herpesvirus by Interacting with Viral mRNAs

• Published in: Viruses 2022-09, Vol.14 (10), p.2083
• Main Authors: Serfecz, Jacquelyn C, Hong, Yuan, Gay, Lauren A, Shekhar, Ritu, Turner, Peter C, Renne, Rolf
• Format: Article
• Language: English
• Subjects: Analysis; Antiviral activity; Antiviral Agents - metabolism; Binding sites; Care and treatment; Cell culture; Complications and side effects; DEAD-box RNA Helicases - genetics; DEAD-box RNA Helicases - metabolism; deadbox helicases; Diagnosis; DNA helicase; DNA Helicases - genetics; Effusion; Gene Expression Regulation, Viral; Genomes; Herpes; Herpesvirus 8, Human - physiology; Herpesvirus diseases; HIV; Human immunodeficiency virus; Humans; Immune system; Immunoprecipitation; Immunotherapy; Infections; innate immunity; Interferon; Interferon Type I - metabolism; Kaposi's sarcoma; Kaposis sarcoma; KSHV; Latency; Lymphoma; Messenger RNA; Next-generation sequencing; Patient outcomes; pattern recognition receptor; Plasmids; Primary effusion lymphoma; Proteins; Replication; Ribonucleic acid; RNA; RNA helicase; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-binding protein; Sarcoma; Sarcoma, Kaposi; Transfection; Tumorigenesis; type I interferon; Viral infections; Virus Activation - genetics; Virus Latency - genetics; Virus Replication - genetics
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v14102083

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that is the causative agent of primary effusion lymphoma and Kaposi's sarcoma. In healthy carriers, KSHV remains latent, but a compromised immune system can lead to lytic viral replication that increases the probability of tumorigenesis. RIG-I-like receptors (RLRs) are members of the DExD/H box helicase family of RNA binding proteins that recognize KSHV to stimulate the immune system and prevent reactivation from latency. To determine if other DExD/H box helicases can affect KSHV lytic reactivation, we performed a knock-down screen that revealed DHX29-dependent activities appear to support viral replication but, in contrast, DDX24 and DDX49 have antiviral activity. When DDX24 or DDX49 are overexpressed in BCBL-1 cells, transcription of all lytic viral genes and genome replication were significantly reduced. RNA immunoprecipitation of tagged DDX24 and DDX49 followed by next-generation sequencing revealed that the helicases bind to mostly immediate-early and early KSHV mRNAs. Transfection of expression plasmids of candidate KSHV transcripts, identified from RNA pull-down, demonstrated that KSHV mRNAs stimulate type I interferon (alpha/beta) production and affect the expression of multiple interferon-stimulated genes. Our findings reveal that host DExD/H box helicases DDX24 and DDX49 recognize gammaherpesvirus transcripts and convey an antiviral effect in the context of lytic reactivation.