Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) are nonpolyadenylated, untranslated RNAs, exist most abundantly in latently EBV-infected cells, and are expected to show secondary structures with many short stem-loops. Retinoic acid-inducible gene I (RIG-I) is a cytosolic protein that detects viral double-stranded RNA (dsRNA) inside the cell and initiates signaling pathways leading to the induction of protective cellular genes, including type I interferons (IFNs). We investigated whether EBERs were recognized by RIG-I as dsRNA. Transfection of RIG-I plasmid induced IFNs and IFN-stimulated genes (ISGs) in EBV-positive Burkitt's lymphoma (BL) cells, but not in their EBV-negative counterparts or EBER-knockout EBV-infected BL cells. Transfection of EBER plasmid or in vitro-synthesized EBERs induced expression of type I IFNs and ISGs in RIG-I-expressing, EBV-negative BL cells, but not in RIG-I-minus counterparts. EBERs activated RIG-I's substrates, NF-kappaB and IFN regulatory factor 3, which were necessary for type I IFN activation. It was also shown that EBERs co-precipitated with RIG-I. These results indicate that EBERs are recognized by RIG-I and activate signaling to induce type I IFN in EBV-infected cells.
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http://dx.doi.org/10.1038/sj.emboj.7601314 | DOI Listing |
Fish Shellfish Immunol
January 2025
College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute,Guangzhou, Guangzhou, 511400,China. Electronic address:
During viral infection, RIG-I-like receptors (RLRs) are cytoplasmic pattern recognition receptors that recognize and bind to viral RNA components, initiating the transcription of interferon-related genes, inflammatory cytokines and other factors, thereby triggering the cellular production of an antiviral innate immune response. The protein inhibitor of activated signal transducer and activator of transcription (STAT) (PIAS) protein family has become a hot research topic due to its extensive involvement in the regulation of cytokines, inflammatory factors and innate immune signaling pathways. In the present study, we investigated the role of fish PIASy in Singapore grouper iridovirus (SGIV) and red spotted grouper nervous necrosis virus (RGNNV) infections.
View Article and Find Full Text PDFImmune-mediated diseases are common in humans. The immune system is a complex host defense system that evolved to protect us from pathogens, but also plays an important role in homeostatic processes, removing dead or senescent cells, and participating in tumor surveillance. The human immune system has two arms: the older innate immune system, and the newer adaptive immune system.
View Article and Find Full Text PDFMol Immunol
December 2024
The First Affiliated Hospital, Department of Gynaecology and Obstetrics, Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China. Electronic address:
Objective: Phosphoribosylformylglycinamidine synthase (PFAS) is a critical enzyme in de novo synthesis of purine. Innate immunity recognizes tumor derived damage-associated molecular patterns (DAMPs) and initiates the anti-tumor adaptive responses. While the function of PFAS catalyzed de novo synthesis of purine is well proved, its effect on innate immune evasion in cancer is unclear and needs to be further explored.
View Article and Find Full Text PDFNat Immunol
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Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT, USA.
Hum Mol Genet
January 2025
Immunopathology and Viral Reservoir Unit, National Center of Microbiology, Instituto de Salud Carlos III, Majadahonda, 28220, Madrid, Spain.
Retinoic acid inducible gene I (RIG-I)-like receptors (RLRs), including RIG-I, MDA5 and LGP2, recognize viral RNA to mount an antiviral interferon (IFN) response RLRs share three different protein domains: C-terminal domain, DExD/H box RNA helicase domain, and an N-terminal domain with two tandem repeats (CARDs). LGP2 lacks tandem CARD and is not able to induce an IFN response. However, LGP2 positively enhances MDA5 and negatively regulates RIG-I signaling.
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