RESUMEN
The role of N6-methyladenosine (m6A) modifications has increasingly been associated with a diverse set of roles in modulating viruses and influencing the outcomes of viral infection. Here, we report that the landscape of m6A deposition is drastically shifted during Kaposi's sarcoma-associated herpesvirus (KSHV) lytic infection for both viral and host transcripts. In line with previous reports, we also saw an overall decrease in host methylation in favor of viral messenger RNA (mRNA), along with 5' hypomethylation and 3' hypermethylation. During KSHV lytic infection, a major shift in overall mRNA abundance is driven by the viral endoribonuclease SOX, which induces the decay of greater than 70% of transcripts. Here, we reveal that interlukin-6 (IL-6) mRNA, a well-characterized, SOX-resistant transcript, is m6A modified during lytic infection. Furthermore, we show that this modification falls within the IL-6 SOX resistance element, an RNA element in the IL-6 3' untranslated region (UTR) that was previously shown to be sufficient for protection from SOX cleavage. We show that the presence of this m6A modification is essential to confer SOX resistance to the IL-6 mRNA. We next show that this modification recruits the m6A reader YTHDC2 and found that YTHDC2 is necessary for the escape of the IL-6 transcript. These results shed light on how the host cell has evolved to use RNA modifications to circumvent viral manipulation of RNA fate during KSHV infection.
Asunto(s)
Endorribonucleasas/metabolismo , ARN Helicasas/metabolismo , Estabilidad del ARN/fisiología , Adenosina/análogos & derivados , Adenosina/genética , Adenosina/metabolismo , Línea Celular Tumoral , Endorribonucleasas/genética , Expresión Génica/genética , Regulación Viral de la Expresión Génica/genética , Células HEK293 , Infecciones por Herpesviridae/genética , Infecciones por Herpesviridae/virología , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/patogenicidad , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Metilación , ARN Helicasas/genética , Estabilidad del ARN/genética , ARN Mensajero/metabolismo , ARN Viral/genética , Proteínas Virales/metabolismo , Replicación Viral/genéticaRESUMEN
For over a decade, studies of messenger RNA regulation have revealed an unprecedented level of connectivity between the RNA pool and global gene expression. These connections are underpinned by a vast array of RNA elements that coordinate RNA-protein and RNA-RNA interactions, each directing mRNA fate from transcription to translation. Consequently, viruses have evolved an arsenal of strategies to target these RNA features and ultimately take control of the pathways they influence, and these strategies contribute to the global shutdown of the host gene expression machinery known as "Host Shutoff". This takeover of the host cell is mechanistically orchestrated by a number of non-homologous virally encoded endoribonucleases. Recent large-scale screens estimate that over 70 % of the host transcriptome is decimated by the expression of these viral nucleases. While this takeover strategy seems extraordinarily well conserved, each viral endonuclease has evolved to target distinct mRNA elements. Herein, we will explore each of these RNA structures/sequence features that render messenger RNA susceptible or resistant to viral endonuclease cleavage. By further understanding these targeting and escape mechanisms we will continue to unravel untold depths of cellular RNA regulation that further underscores the integral relationship between RNA fate and the fate of the cell.
Asunto(s)
Endorribonucleasas/genética , Estabilidad del ARN , ARN Mensajero/genética , ARN Viral/genética , Proteínas de Unión al ARN/genética , Proteínas Virales/genética , Virus/genética , Endorribonucleasas/metabolismo , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno/genética , Humanos , Biosíntesis de Proteínas , ARN Mensajero/metabolismo , ARN Viral/metabolismo , Proteínas de Unión al ARN/metabolismo , Ribosomas/genética , Ribosomas/metabolismo , Transducción de Señal , Especificidad por Sustrato , Proteínas Virales/metabolismo , Virosis/genética , Virosis/metabolismo , Virosis/patología , Virosis/virología , Virus/clasificación , Virus/crecimiento & desarrollo , Virus/patogenicidadRESUMEN
Kaposi's sarcoma-associated herpesvirus (KSHV) induces life-long infections and has evolved many ways to exert extensive control over its host's transcriptional and post-transcriptional machinery to gain better access to resources and dampened immune sensing. The hallmark of this takeover is how KSHV reshapes RNA fate both to control expression of its own gene but also that of its host. From the nucleus to the cytoplasm, control of RNA expression, localization, and decay is a process that is carefully tuned by a multitude of factors and that can adapt or react to rapid changes in the environment. Intriguingly, it appears that KSHV has found ways to co-opt each of these pathways for its own benefit. Here we provide a comprehensive review of recent work in this area and in particular recent advances on the post-transcriptional modifications front. Overall, this review highlights the myriad of ways KSHV uses to control RNA fate and gathers novel insights gained from the past decade of research at the interface of RNA biology and the field of KSHV research.
