CAGE sequencing of LASV infected Vero Cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Mammarenavirus lassaense
PROVIDER: GSE148122 | GEO | 2020/05/31
REPOSITORIES: GEO
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Project description:RNA viruses are a major threat to global human health. The life cycles of many highly pathogenic RNA viruses like influenza A virus (IAV) and Lassa virus depends on host mRNA, as viral polymerases cleave 5′m7G-capped host transcripts to prime viral mRNA synthesis (‘cap-snatching’). We hypothesized that start codons within cap-snatched host transcripts could drive the expression of chimeric human-viral coding sequences. Here, we report the existence of this mechanism of gene origination (‘start-snatching’), which creates, depending on the translatability of the viral UTRs, human-virus protein chimeras either as N-terminally extended viral proteins or entirely novel polypeptides by genetic overprinting. We show that both types of chimeric proteins are made in IAV-infected cells, can generate T cell responses and contribute to virulence. Our results indicate that IAV, and likely a multitude of other human-, animal- and plant-viruses, use this host-dependent mechanism to expand their proteome diversity during infection.
2020-05-15 | GSE148245 | GEO
Project description:Influenza A virus (IAV) lacks the enzyme for adding 5’ caps to its RNAs, and thus snatches the 5’ ends of host capped RNAs to prime transcription. Neither the preference of the host RNA sequences snatched, nor the effect of “cap-snatching” on host processes has been completely defined. Previous studies of influenza cap-snatching used poly(A)-selected RNA from infected cells or relied solely on annotated host protein-coding genes to define host mRNAs selected by the virus. To examine the substrate-product relationship between all host RNAs, including non-coding RNAs, and viral RNAs, we used an unbiased approach to identify the host and viral capped RNAs from IAV-infected cells. We demonstrate that IAV predominantly snatches caps from non-coding host RNAs, particularly U1 and U2 small nuclear RNAs (snRNAs). Because snRNAs regulate host mRNA processing, cap-snatching of snRNAs may constitute a means by which IAV hijacks host cell metabolism.
2015-11-23 | GSE67493 | GEO
Project description:Influenza A virus (IAV) lacks the enzyme for adding 5â caps to its RNAs, and thus snatches the 5â ends of host capped RNAs to prime transcription. Neither the preference of the host RNA sequences snatched, nor the effect of âcap-snatchingâ on host processes has been completely defined. Previous studies of influenza cap-snatching used poly(A)-selected RNA from infected cells or relied solely on annotated host protein-coding genes to define host mRNAs selected by the virus. To examine the substrate-product relationship between all host RNAs, including non-coding RNAs, and viral RNAs, we used an unbiased approach to identify the host and viral capped RNAs from IAV-infected cells. We demonstrate that IAV predominantly snatches caps from non-coding host RNAs, particularly U1 and U2 small nuclear RNAs (snRNAs). Because snRNAs regulate host mRNA processing, cap-snatching of snRNAs may constitute a means by which IAV hijacks host cell metabolism. examine caps snatched by influenza virus A
2015-11-23 | E-GEOD-67493 | biostudies-arrayexpress
Project description:Influenza A virus (IAV) is a major respiratory pathogen that causes severe illness and mortality worldwide. IAV critically depends on host factors for multiple functions that are not encoded by the viral genome. Notably, the IAV RNA-dependent RNA polymerase (RdRP) complex lacks intrinsic 7-methylguanosine (m7G) capping activity and instead “snatches” the 5’m7G caps and the adjacent 10-15nts of host transcripts to prime viral mRNA production, allowing viral transcripts to be recognized by the host translation machinery. We developed a new approach to simultaneously assay the 5’ ends of host and viral transcripts in infected cells and identify the host capsnatch origins for viral mRNAs. We used this technique to study the progression of IAV infection in nuclear and cytoplasmic compartiments and determined that the RdRP complex has specific sequence preferences that results in preferential capsnatching and avoidance of sub-populations of host RNAs, which can be reverted by the addition of a cap-snatch inhibitor. Notably, genes avoided by CapSnatch Seq have biological functions enriched for mRNA processing, translation, and viral replication. This selectivity and functional enrichment of avoided genes is conserved among capsnatching viruses including Influenza B Virus and Lymphocytic Choriomeningitis Virus, despite differences in RdRP domains and subcellular locations of RNA substrates. This suggests that this preference convergently arose as a viral strategy to allow cap-snatching viruses to avoid targeting genes necessary for its own replication.
2017-08-09 | GSE85474 | GEO
Project description:Viruses are master remodelers of the host cell environment in support of infection and virus production. For example, viruses typically regulate cell gene expression through modulating canonical cell promoter activity. Here, we show that Epstein Barr virus (EBV) replication causes “de novo” transcription initiation at 29,674 new transcription start sites throughout the cell genome. De novo transcription initiation is facilitated in part by the unique properties of the viral pre-initiation complex (vPIC) that binds a simple TATT[T/A]AA, TATA box-like sequence and activates transcription with minimal support by additional transcription factors. Other de novo promoters are driven by the viral transcription factors, Zta and Rta and are influenced by directional proximity to existing canonical cell promoters, a configuration that fosters transcription through existing promoters and transcriptional interference. These studies reveal a new way that viruses interact with the host transcriptome and shed light on primal features driving promoter function.
2024-02-01 | GSE240011 | GEO
Project description:The influenza polymerase cleaves host RNAs ~10–13 nucleotides downstream of their 5′ ends and uses this capped fragment to prime viral mRNA synthesis. To better understand this process of cap snatching, we used high-throughput sequencing to determine the 5′ ends of A/WSN/33 (H1N1) influenza mRNAs. The sequences provided clear evidence for nascent-chain realignment during transcription initiation and revealed a strong influence of the viral template on the frequency of realignment. After accounting for the extra nucleotides inserted through realignment, analysis of the capped fragments indicated that the different viral mRNAs were each prepended with a common set of sequences and that the polymerase often cleaved host RNAs after a purine and often primed transcription on a single base pair to either the terminal or penultimate residue of the viral template. We also developed a bioinformatic approach to identify the targeted host transcripts despite limited information content within snatched fragments and found that small nuclear RNAs and small nucleolar RNAs contributed the most abundant capped leaders. These results provide insight into the mechanism of viral transcription initiation and reveal the diversity of the cap-snatched repertoire, showing that noncoding transcripts as well as mRNAs are used to make influenza mRNAs.
2015-04-23 | GSE65101 | GEO
Project description:The influenza polymerase cleaves host RNAs ~10–13 nucleotides downstream of their 5′ ends and uses this capped fragment to prime viral mRNA synthesis. To better understand this process of cap snatching, we used high-throughput sequencing to determine the 5′ ends of A/WSN/33 (H1N1) influenza mRNAs. The sequences provided clear evidence for nascent-chain realignment during transcription initiation and revealed a strong influence of the viral template on the frequency of realignment. After accounting for the extra nucleotides inserted through realignment, analysis of the capped fragments indicated that the different viral mRNAs were each prepended with a common set of sequences and that the polymerase often cleaved host RNAs after a purine and often primed transcription on a single base pair to either the terminal or penultimate residue of the viral template. We also developed a bioinformatic approach to identify the targeted host transcripts despite limited information content within snatched fragments and found that small nuclear RNAs and small nucleolar RNAs contributed the most abundant capped leaders. These results provide insight into the mechanism of viral transcription initiation and reveal the diversity of the cap-snatched repertoire, showing that noncoding transcripts as well as mRNAs are used to make influenza mRNAs. Sixteen datasets were generated, corresponding to template-switching 5’-RACE libraries of 1) each viral RNA, 2) a time-course of NS1 viral RNA, or 3) CIP-TAP libraries of NS1 and PB2. Libraries contain random barcodes of length 5 (NS1_TS, PB2_TS, NS1_5R, PB2_5R) or 9 (other datasets) at the start of each read, and at least three guanosine residues for the template-switching datasets. See methods of accompanying paper for further details. Samples were sequenced on an Illumina HiSeq 2000.
2015-04-23 | E-GEOD-65101 | biostudies-arrayexpress
Project description:Multiple processes exist in a cell to ensure continuousproduction of essential proteins either through cap-dependent or cap-independent translation processes. Viruses depend on the host translation machinery for viral protein synthesis. Therefore, viruses have evolved clever strategies to utilize the host translation machinery. Earlier studies have shown that genotype1 hepatitis E virus (g1-HEV) utilizes both cap-dependent and cap-independent translation machineries for its replication and proliferation. Cap-independent translation in g1-HEV is driven by an eighty seven nucleotide-long RNA element which acts as a noncanonical, internal ribosome entry site like (IRESl) element. Here, we have identified the RNA-protein interactome of the HEV IRESl element and characterized the functional significance of some of its components. Our study reveals indispensable roles of host ribosomal proteinRPL5 and DHX9 (RNA helicase A) in mediating efficient translation from the IRESlelement and establish the function of HEV IRESl as a bonafide internal ribosome entry site.
2023-06-25 | PXD031009 | Pride
Project description:Virus infection may shut off host protein synthesis in order to achieve the replicative advantage over host cells. It is well known that human pathogenic viruses, particularly the picornaviruses, can block host protein synthesis by cleavage or inhibition of eukaryotic initiation factors (eIFs). In this study we found a novel mechanism that microRNA (miRNA) is involved in viral pathogenesis. Infection of enteroviruses can disturb the expression of host miRNAs, in which miR-141 is up-regulated and inhibits host protein synthesis by post-transcriptional repression of the target gene eIF4E, a key element for cap-dependent translation of host proteins. Knockdown of miR-141 by a specific siRNA, antagomiR-141, could restore host eIF4E expression, delay the occurrence of cytopathic effect (CPE), and impair virus propagation. We demonstrated that EV71 infection could increase early growth response 1 (EGR1) expression which induced miR-141 causing the eIF4E suppression; while silencing of EGR1 attenuated virus production. Our results suggest that enterovirus infection causes the EGR1-mediated upregulation of host miR-141, further lead to the translational switch from cap-dependent to cap-independent protein synthesis in the host cells, an environmental beneficial for viral propagation. This novel mechanism may highlight a new approach for future development of antiviral therapy. Enteroviruses in the Picornaviridae family are important human pathogens which can cause fatal diseases, including cardiopulmonary failure, aseptic meningitis, paralysis, myocarditis, and encephalomyelitis. Virus infection may induce shutoff of host protein synthesis, particularly in picornavirus, whose protein translation is cap-independent. It is known that poliovirus 2A protease cleaves eIF4G, a scaffold component of mammalian cell translational complex, leading to the shut down of host protein synthesis. Nevertheless, the cleavage of eIF4G may not be sufficient for the complete shutoff of host protein synthesis. Previous studies showed that cleavage of polyA-binding protein (PABP) by viral protease 3C and dephosphorylation of the translational repressor, eIF4E binding protein 1 (4E-BP1), also contribute to this process. The cap-binding protein, eIF4E, is the most crucial factor in determining whether cap-dependent or -independent translation takes place. The mechanism by which viral infection modulates host cell protein synthesis through interfering eIF4E expression is not yet known. miRNAs are a newly discovered class of small non-protein-coding RNAs that may act via endogenous RNA interference. Our understanding of its role in the dynamic interplay between virus and host components is quite limited. Since both virus infection and miRNAs could hinder cellular protein synthesis, whether miRNAs are involved during virus infection in shutting off host protein synthesis is still unknown. To address this issue, we analyze the altered gene and microRNA expression after EV71 infection. ***This submission represents the mRNA expression component of the study only***
2011-01-03 | E-GEOD-15323 | biostudies-arrayexpress
Project description:Influenza virus polymerase transcribes or replicates the segmented RNA genome (vRNA) into respectively viral mRNA or full-length copies and initiates RNA synthesis by binding the conserved 3' and 5' vRNA ends (the promoter). In recent structures of promoter-bound polymerase, the cap-binding and endonuclease domains are configured for cap snatching, which generates capped transcription primers. Here, we present a FluB polymerase structure with a bound complementary cRNA 5' end that exhibits a major rearrangement of the subdomains within the C-terminal two-thirds of PB2 (PB2-C). Notably, the PB2 nuclear localization signal (NLS)- containing domain translocates ~90 A ̊ to bind to the endonuclease domain. FluA PB2-C alone and RNA-free FluC polymerase are similarly arranged. Biophysical and cap-dependent endonuclease assays show that in solution the polymerase explores different conformational distributions depending on which RNA is bound. The inherent flexibility of the polymerase allows it to adopt alternative conformations that are likely important during polymerase maturation into active progeny RNPs.</br></br>Extra contact information:</br><a href="mailto:cusack@embl.fr">Stephen Cusack</a>, EMBL Grenoble Outstation, Unit of Virus Host-Cell Interactions, France ( corresponding author and lab head )
2016-01-04 | PXD002234 | Pride