Abstract
Infection of cells by respiratory syncytial virus induces the formation of cytoplasmic inclusion bodies (IBs) where all the components of the viral RNA polymerase complex are concentrated. However, the exact organization and function of these IBs remain unclear. In this study, we use conventional and super-resolution imaging to dissect the internal structure of IBs. We observe that newly synthetized viral mRNA and the viral transcription anti-terminator M2-1 concentrate in IB sub-compartments, which we term “IB-associated granules” (IBAGs). In contrast, viral genomic RNA, the nucleoprotein, the L polymerase and its cofactor P are excluded from IBAGs. Live imaging reveals that IBAGs are highly dynamic structures. Our data show that IBs are the main site of viral RNA synthesis. They further suggest that shortly after synthesis in IBs, viral mRNAs and M2-1 transiently concentrate in IBAGs before reaching the cytosol and suggest a novel post-transcriptional function for M2-1.
Highlights
Infection of cells by respiratory syncytial virus induces the formation of cytoplasmic inclusion bodies (IBs) where all the components of the viral RNA polymerase complex are concentrated
In order to determine if these structures are sites of viral RNA synthesis, we performed nascent RNA staining on respiratory syncytial virus (RSV)-infected HEp-2 cells
These results show that IBs are sites of viral RNA synthesis
Summary
Infection of cells by respiratory syncytial virus induces the formation of cytoplasmic inclusion bodies (IBs) where all the components of the viral RNA polymerase complex are concentrated. IBs observed in RSVinfected cells were shown to harbor viral proteins involved in transcription and replication of the viral genome, namely N, P, L and M2-124–28, as well as viral genomic RNA26–28. We show that newly synthetized viral RNA is present in IBs of cells infected by RSV, indicating that these inclusions are sites of viral RNA synthesis. We identified functional sub-compartments within IBs that we call “IB-associated granules (IBAGs)” These IBAGs concentrate newly synthetized viral mRNA and M2-1, but exclude proteins N, P and L and the genomic RNA. Based on their protein and mRNA content and on their dynamic behavior, we propose that IBAGs are viral mRNA sorting stations in which M2-1 plays a key and hitherto undescribed role
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
