RESUMO
Adenosine-to-inosine RNA editing is a major contributor to transcriptome diversity in animals with far-reaching biological consequences. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of several human malignancies including primary effusion lymphoma (PEL). The extent of RNA editing within the KSHV transcriptome is unclear as is its contribution to the viral lifecycle. Here, we leverage a combination of biochemical and genomic approaches to determine the RNA editing landscape in host- and KSHV transcriptomes during both latent and lytic replication in PEL. Analysis of RNA editomes reveals it is dynamic, with increased editing upon reactivation and the potential to deregulate pathways critical for latency and tumorigenesis. In addition, we identify conserved RNA editing events within a viral microRNA and discover their role in miRNA biogenesis as well as viral infection. Together, these results describe the editome of PEL cells as well as a critical role for A-to-I editing in the KSHV lifecycle.
Assuntos
Herpesvirus Humano 8 , Linfoma de Efusão Primária , MicroRNAs , Sarcoma de Kaposi , Animais , Humanos , Herpesvirus Humano 8/metabolismo , Latência Viral/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Replicação Viral/genética , Regulação Viral da Expressão GênicaRESUMO
RIG-I-like receptors (RLRs) are involved in the discrimination of self versus non-self via the recognition of double-stranded RNA (dsRNA). Emerging evidence suggests that immunostimulatory dsRNAs are ubiquitously expressed but are disrupted or sequestered by cellular RNA binding proteins (RBPs). TDP-43 is an RBP associated with multiple neurological disorders and is essential for cell viability. Here, we demonstrate that TDP-43 regulates the accumulation of immunostimulatory dsRNA. The immunostimulatory RNA is identified as RNA polymerase III transcripts, including 7SL and Alu retrotransposons, and we demonstrate that the RNA-binding activity of TDP-43 is required to prevent immune stimulation. The dsRNAs activate a RIG-I-dependent interferon (IFN) response, which promotes necroptosis. Genetic inactivation of the RLR-pathway rescues the interferon-mediated cell death associated with loss of TDP-43. Collectively, our study describes a role for TDP-43 in preventing the accumulation of endogenous immunostimulatory dsRNAs and uncovers an intricate relationship between the control of cellular gene expression and IFN-mediated cell death.