Influenza A virus preferentially snatches non-coding RNA caps
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE67493 | GEO | 2015/11/23
SECONDARY ACCESSION(S): PRJNA280061
REPOSITORIES: GEO
Similar Datasets
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: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:We report a novel mechanism of gene origination in the segmented negative sense viruses (sNSVs), including IAV and LASV. During replication, these viruses use "snatched" host caps to prime their own transcription (cap-snatching). We show that a proportion of cap-snatched host sequences contain translational start codons (AUGs), that are recognized by the host ribosome. This allows for the translation of host and viral “untranslated regions” (UTRs) to create N-terminally extended viral proteins or entirely novel polypeptides by genetic overprinting.
2020-05-31 | GSE148122 | GEO
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: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:The nuclear cap-binding complex (CBC) stimulates multiple steps in several RNA maturation pathways, but how it functions in humans is incompletely understood. For small capped RNAs like pre-snRNAs, the CBC recruits PHAX. Here, we identify the CBCAP complex, composed of CBC, Ars2 and PHAX, and show that both CBCAP and CBC-Ars2 complexes can be reconstituted from recombinant proteins. Ars2 stimulates PHAX binding to the CBC as well as snRNAs 3'-end processing, hereby coupling maturation with export. In vivo, CBC and Ars2 bind similar capped non-coding and coding RNAs, and stimulate their 3M-bM-^@M-^Y-end processing. Strongest effects are displayed for cap-proximal polyadenylation sites, thereby favoring premature transcription termination. Ars2 functions in part through the mRNA 3M-bM-^@M-^Y-end cleavage factor CLP1, which binds RNA Polymerase II through PCF11. Ars2 is thus a major CBC effector that stimulates functional and cryptic 3'-end processing sites. In total 12 samples; 4 control IP, 2 Flag- Ars2 IP and 2 Flag-CBP20 IP; 2 control FFL siRNA and 2 siRNA Ars2
2013-11-08 | E-GEOD-52131 | biostudies-arrayexpress
Project description:The nuclear cap-binding complex (CBC) stimulates multiple steps in several RNA maturation pathways, but how it functions in humans is incompletely understood. For small capped RNAs like pre-snRNAs, the CBC recruits PHAX. Here, we identify the CBCAP complex, composed of CBC, Ars2 and PHAX, and show that both CBCAP and CBC-Ars2 complexes can be reconstituted from recombinant proteins. Ars2 stimulates PHAX binding to the CBC as well as snRNAs 3'-end processing, hereby coupling maturation with export. In vivo, CBC and Ars2 bind similar capped non-coding and coding RNAs, and stimulate their 3’-end processing. Strongest effects are displayed for cap-proximal polyadenylation sites, thereby favoring premature transcription termination. Ars2 functions in part through the mRNA 3’-end cleavage factor CLP1, which binds RNA Polymerase II through PCF11. Ars2 is thus a major CBC effector that stimulates functional and cryptic 3'-end processing sites.
2013-11-08 | GSE52131 | GEO
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
Project description:Influenza A virus (IAV) is a threat to mankind because it generates yearly epidemics and poorly predictable sporadic pandemics with catastrophic potential. Influenza has a small RNA genome (~14 Kb) composed of 8 mini-chromosomes (segments). Segments encode both structural proteins and proteins expressed only during infection. Segments are constituted by a 5’UTR followed by a coding region and a 3’UTR. Transcription of IAV RNA into mRNA depends on host RNA Polymerase II, as the viral polymerase cleaves 5’ capped cellular nascent transcripts to be used as primers to initiate mRNA synthesis. We hypothesized that host nascent transcripts bearing AUG could generate upstream ORFs in the viral segments, a phenomenon that would depend on the translatability of the viral 5’UTRs. Using orthogonal datasets we report the existence of this mechanism, which generate host-virus chimeric proteins. We show that most segments encode proteins in this manner, expanding the proteome diversity of IAV in infected cells. Host-virus chimeric proteins are conserved across IAV strains, pointing to an evolutionary conservation of function achieved by sampling of the evolutionary space before gene fixation. Thus, we discover a mechanism that generate human-virus chimeric proteins during infection.
2020-06-25 | GSE128519 | GEO