RESUMEN
The roles of virus-derived small RNAs (vsRNAs) have been studied in plants and insects. However, the generation and function of small RNAs from cytoplasmic RNA viruses in mammalian cells remain unexplored. This study describes four vsRNAs that were detected in enterovirus 71-infected cells using next-generation sequencing and northern blots. Viral infection produced substantial levels (>10(5) copy numbers per cell) of vsRNA1, one of the four vsRNAs. We also demonstrated that Dicer is involved in vsRNA1 generation in infected cells. vsRNA1 overexpression inhibited viral translation and internal ribosomal entry site (IRES) activity in infected cells. Conversely, blocking vsRNA1 enhanced viral yield and viral protein synthesis. We also present evidence that vsRNA1 targets stem-loop II of the viral 5' untranslated region and inhibits the activity of the IRES through this sequence-specific targeting. Our study demonstrates the ability of a cytoplasmic RNA virus to generate functional vsRNA in mammalian cells. In addition, we also demonstrate a potential novel mechanism for a positive-stranded RNA virus to regulate viral translation: generating a vsRNA that targets the IRES.
Asunto(s)
Regiones no Traducidas 5' , Enterovirus Humano A/genética , Regulación Viral de la Expresión Génica , Biosíntesis de Proteínas , ARN Pequeño no Traducido/metabolismo , ARN Viral/metabolismo , Línea Celular Tumoral , Regulación hacia Abajo , Humanos , Ribonucleasa III/metabolismo , Proteínas Virales/biosíntesisRESUMEN
The role of virus-derived small RNAs (vsRNAs) has been identified as an antiviral mechanism in plants, arthropods, and nematodes. Although mammalian DNA viruses have been observed to encode functional miRNAs, whether RNA virus infection generates functional vsRNAs remains under discussion. This article reviews the most recent reports regarding pathways for generating vsRNAs and the identified vsRNA activity in mammalian cells infected with RNA viruses. We also discuss several hypotheses regarding the roles of mammalian vsRNAs and comment on the potential directions for this research field.
Asunto(s)
Virus ADN/genética , Mamíferos/virología , MicroARNs/genética , ARN Interferente Pequeño/genética , Animales , Mamíferos/inmunología , Interferencia de ARN , Virus ARNRESUMEN
Enterovirus 71 (EV71) infections can cause hand, foot, and mouth disease with severe neurological complications. Because no clinical drug is available for treating EV71 infections, developing an efficient antiviral medication against EV71 infection is crucial. This study indicated that 6-bromo-2-[1-(2,5-dimethylphenyl)-5-methyl-1H-pyrazol-4-yl] quinoline-4-carboxylic acid (BPR-3P0128) exhibits excellent antiviral activity against EV71 (EC50 = 0.0029 µM). BPR-3P0128 inhibits viral replication during the early post infection stage, targets EV71 RNA-dependent RNA polymerase and VPg uridylylation, and also reduces viral RNA accumulation levels and inhibits viral replication of EV71.