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1.
bioRxiv ; 2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39211142

RESUMEN

Proper recognition of viral pathogens is an essential part of the innate immune response. A common viral replicative intermediate and chemical signal that cells use to identify pathogens is the presence of a triphosphorylated 5' end (5'ppp) RNA, which activates the cytosolic RNA sensor RIG-I and initiates downstream antiviral signaling. While 5'pppRNA generated by viral RNA-dependent RNA polymerases (RdRps) can be a potent activator of the immune response, endogenous RNA polymerase III (RNAPIII) transcripts can retain the 5'pppRNA generated during transcription and induce a RIG-I-mediated immune response. We have previously shown that host RNA triphosphatase dual-specificity phosphatase 11 (DUSP11) can act on both host and viral RNAs, altering their levels and reducing their ability to induce RIG-I activation. Our previous work explored how artificially altered DUSP11 can impact immune activation, prompting further exploration into natural contexts of altered DUSP11. Here, we have identified viral DUSP11 homologs (vDUSP11s) present in some avipoxviruses. Consistent with the known functions of endogenous DUSP11, we have shown that expression of vDUSP11s: 1) reduces levels of endogenous RNAPIII transcripts, 2) reduces a cell's sensitivity to 5'pppRNA-mediated immune activation, and 3) restores virus infection defects seen in the absence of DUSP11. Our results identify a virus-relevant context where DUSP11 activity has been co-opted to alter RNA metabolism and influence the outcome of infection.

2.
bioRxiv ; 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38712082

RESUMEN

PARP14 is a 203 kDa multi-domain protein that is primarily known as an ADP-ribosyltransferase, and is involved in a variety of cellular functions including DNA damage, microglial activation, inflammation, and cancer progression. In addition, PARP14 is upregulated by interferon (IFN), indicating a role in the antiviral response. Furthermore, PARP14 has evolved under positive selection, again indicating that it is involved in host-pathogen conflict. We found that PARP14 is required for increased IFN-I production in response to coronavirus infection lacking ADP-ribosylhydrolase (ARH) activity and poly(I:C), however, whether it has direct antiviral function remains unclear. Here we demonstrate that the catalytic activity of PARP14 enhances IFN-I and IFN-III responses and restricts ARH-deficient murine hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. To determine if PARP14's antiviral functions extended beyond CoVs, we tested the ability of herpes simplex virus 1 (HSV-1) and several negative-sense RNA viruses, including vesicular stomatitis virus (VSV), Ebola virus (EBOV), and Nipah virus (NiV), to infect A549 PARP14 knockout (KO) cells. HSV-1 had increased replication in PARP14 KO cells, indicating that PARP14 restricts HSV-1 replication. In contrast, PARP14 was critical for the efficient infection of VSV, EBOV, and NiV, with EBOV infectivity at less than 1% of WT cells. A PARP14 active site inhibitor had no impact on HSV-1 or EBOV infection, indicating that its effect on these viruses was independent of its catalytic activity. These data demonstrate that PARP14 promotes IFN production and has both pro- and anti-viral functions targeting multiple viruses.

3.
Nature ; 618(7964): 358-364, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37225987

RESUMEN

The ability to switch between different lifestyles allows bacterial pathogens to thrive in diverse ecological niches1,2. However, a molecular understanding of their lifestyle changes within the human host is lacking. Here, by directly examining bacterial gene expression in human-derived samples, we discover a gene that orchestrates the transition between chronic and acute infection in the opportunistic pathogen Pseudomonas aeruginosa. The expression level of this gene, here named sicX, is the highest of the P. aeruginosa genes expressed in human chronic wound and cystic fibrosis infections, but it is expressed at extremely low levels during standard laboratory growth. We show that sicX encodes a small RNA that is strongly induced by low-oxygen conditions and post-transcriptionally regulates anaerobic ubiquinone biosynthesis. Deletion of sicX causes P. aeruginosa to switch from a chronic to an acute lifestyle in multiple mammalian models of infection. Notably, sicX is also a biomarker for this chronic-to-acute transition, as it is the most downregulated gene when a chronic infection is dispersed to cause acute septicaemia. This work solves a decades-old question regarding the molecular basis underlying the chronic-to-acute switch in P. aeruginosa and suggests oxygen as a primary environmental driver of acute lethality.


Asunto(s)
Enfermedad Aguda , Enfermedad Crónica , Genes Bacterianos , Oxígeno , Infecciones por Pseudomonas , Pseudomonas aeruginosa , ARN Bacteriano , Animales , Humanos , Oxígeno/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidad , Infecciones por Pseudomonas/complicaciones , Infecciones por Pseudomonas/microbiología , Infecciones por Pseudomonas/patología , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , Fibrosis Quística/microbiología , Heridas y Lesiones/microbiología , Ubiquinona/biosíntesis , Anaerobiosis , Genes Bacterianos/genética , Sepsis/complicaciones , Sepsis/microbiología
4.
PLoS Comput Biol ; 18(11): e1010131, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36413582

RESUMEN

The concept of a nucleic acid barcode applied to pathogen genomes is easy to grasp and the many possible uses are straightforward. But implementation may not be easy, especially when growing through multiple generations or assaying the pathogen long-term. The potential problems include: the barcode might alter fitness, the barcode may accumulate mutations, and construction of the marked pathogens may result in unintended barcodes that are not as designed. Here, we generate approximately 5,000 randomized barcodes in the genome of the prototypic small DNA virus murine polyomavirus. We describe the challenges faced with interpreting the barcode sequences obtained from the library. Our Illumina NextSeq sequencing recalled much greater variation in barcode sequencing reads than the expected 5,000 barcodes-necessarily stemming from the Illumina library processing and sequencing error. Using data from defined control virus genomes cloned into plasmid backbones we develop a vetted post-sequencing method to cluster the erroneous reads around the true virus genome barcodes. These findings may foreshadow problems with randomized barcodes in other microbial systems and provide a useful approach for future work utilizing nucleic acid barcoded pathogens.


Asunto(s)
Virus ADN , Ácidos Nucleicos , Ratones , Animales , Virus ADN/genética
5.
PLoS Pathog ; 17(5): e1009582, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33999949

RESUMEN

Circular RNAs (circRNAs) are a conserved class of RNAs with diverse functions, including serving as messenger RNAs that are translated into peptides. Here we describe circular RNAs generated by human polyomaviruses (HPyVs), some of which encode variants of the previously described alternative large T antigen open reading frame (ALTO) protein. Circular ALTO RNAs (circALTOs) can be detected in virus positive Merkel cell carcinoma (VP-MCC) cell lines and tumor samples. CircALTOs are stable, predominantly located in the cytoplasm, and N6-methyladenosine (m6A) modified. The translation of MCPyV circALTOs into ALTO protein is negatively regulated by MCPyV-generated miRNAs in cultured cells. MCPyV ALTO expression increases transcription from some recombinant promoters in vitro and upregulates the expression of multiple genes previously implicated in MCPyV pathogenesis. MCPyV circALTOs are enriched in exosomes derived from VP-MCC lines and circALTO-transfected 293T cells, and purified exosomes can mediate ALTO expression and transcriptional activation in MCPyV-negative cells. The related trichodysplasia spinulosa polyomavirus (TSPyV) also expresses a circALTO that can be detected in infected tissues and produces ALTO protein in cultured cells. Thus, human polyomavirus circRNAs are expressed in human tumors and infected tissues and express proteins that have the potential to modulate the infectious and tumorigenic properties of these viruses.


Asunto(s)
Antígenos Virales de Tumores/genética , Carcinoma de Células de Merkel/virología , Poliomavirus de Células de Merkel/genética , Infecciones por Polyomavirus/virología , ARN Circular/genética , Infecciones Tumorales por Virus/virología , Exosomas , Regulación Viral de la Expresión Génica , Células HEK293 , Humanos , MicroARNs/genética , ARN Mensajero/genética , ARN Viral/genética
7.
Genes Dev ; 34(23-24): 1697-1712, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33184222

RESUMEN

Deciphering the mechanisms that regulate the sensitivity of pathogen recognition receptors is imperative to understanding infection and inflammation. Here we demonstrate that the RNA triphosphatase dual-specificity phosphatase 11 (DUSP11) acts on both host and virus-derived 5'-triphosphate RNAs rendering them less active in inducing a RIG-I-mediated immune response. Reducing DUSP11 levels alters host triphosphate RNA packaged in extracellular vesicles and induces enhanced RIG-I activation in cells exposed to extracellular vesicles. Virus infection of cells lacking DUSP11 results in a higher proportion of triphosphorylated viral transcripts and attenuated virus replication, which is rescued by reducing RIG-I expression. Consistent with the activity of DUSP11 in the cellular RIG-I response, mice lacking DUSP11 display lower viral loads, greater sensitivity to triphosphorylated RNA, and a signature of enhanced interferon activity in select tissues. Our results reveal the importance of controlling 5'-triphosphate RNA levels to prevent aberrant RIG-I signaling and demonstrate DUSP11 as a key effector of this mechanism.


Asunto(s)
Proteína 58 DEAD Box/inmunología , Fosfatasas de Especificidad Dual/inmunología , Fosfatasas de Especificidad Dual/metabolismo , ARN/inmunología , Virosis/inmunología , Animales , Línea Celular , Células HEK293 , Interacciones Huésped-Patógeno , Humanos , Inmunidad Innata/genética , Inmunidad Innata/inmunología , Interferones/metabolismo , Liposomas/inmunología , Ratones , Ratones Endogámicos C57BL , Polifosfatos , Virus ARN/fisiología , ARN Viral/metabolismo , Replicación Viral/genética
9.
medRxiv ; 2020 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-32793925

RESUMEN

Since the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, there have been demands on the testing infrastructure that have strained testing capacity. As a simplification of method, we confirm the efficacy of RNA extraction-free RT-qPCR and saline as an alternative patient sample storage buffer. In addition, amongst potential reagent shortages, it has sometimes been difficult to obtain inactivated viral particles. We have therefore also characterized armored SARS-CoV-2 RNA from Asuragen as an alternative diagnostic standard to ATCC genomic SARS-CoV-2 RNA and heat inactivated virions and provide guidelines for its use in RT-qPCR.

10.
PLoS Pathog ; 15(5): e1007756, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31095648

RESUMEN

ADP-ribosylation is a ubiquitous post-translational addition of either monomers or polymers of ADP-ribose to target proteins by ADP-ribosyltransferases, usually by interferon-inducible diphtheria toxin-like enzymes known as PARPs. While several PARPs have known antiviral activities, these activities are mostly independent of ADP-ribosylation. Consequently, less is known about the antiviral effects of ADP-ribosylation. Several viral families, including Coronaviridae, Togaviridae, and Hepeviridae, encode for macrodomain proteins that bind to and hydrolyze ADP-ribose from proteins and are critical for optimal replication and virulence. These results suggest that macrodomains counter cellular ADP-ribosylation, but whether PARPs or, alternatively, other ADP-ribosyltransferases cause this modification is not clear. Here we show that pan-PARP inhibition enhanced replication and inhibited interferon production in primary macrophages infected with macrodomain-mutant but not wild-type coronavirus. Specifically, knockdown of two abundantly expressed PARPs, PARP12 and PARP14, led to increased replication of mutant but did not significantly affect wild-type virus. PARP14 was also important for the induction of interferon in mouse and human cells, indicating a critical role for this PARP in the regulation of innate immunity. In summary, these data demonstrate that the macrodomain is required to prevent PARP-mediated inhibition of coronavirus replication and enhancement of interferon production.


Asunto(s)
Infecciones por Coronavirus/virología , Coronavirus/inmunología , Inmunidad Innata/inmunología , Interferones/metabolismo , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Replicación Viral , ADP-Ribosilación , Animales , Coronavirus/efectos de los fármacos , Infecciones por Coronavirus/tratamiento farmacológico , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/metabolismo , Humanos , Inmunidad Innata/efectos de los fármacos , Ratones , Poli(ADP-Ribosa) Polimerasas/química , Poli(ADP-Ribosa) Polimerasas/genética , Dominios Proteicos , Receptor de Interferón alfa y beta/genética , Receptor de Interferón alfa y beta/metabolismo , Virulencia
11.
Proc Natl Acad Sci U S A ; 115(32): 8197-8202, 2018 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-30038017

RESUMEN

Seventy percent of people infected with hepatitis C virus (HCV) will suffer chronic infection, putting them at risk for liver disease, including hepatocellular carcinoma. The full range of mechanisms that render some people more susceptible to chronic infection and liver disease is still being elucidated. XRN exonucleases can restrict HCV replication and may help to resolve HCV infections. However, it is unknown how 5' triphosphorylated HCV transcripts, primary products of the viral polymerase, become susceptible to attack by 5' monophosphate-specific XRNs. Here, we show that the 5' RNA triphosphatase DUSP11 acts on HCV transcripts, rendering them susceptible to XRN-mediated attack. Cells lacking DUSP11 show substantially enhanced HCV replication, and this effect is diminished when XRN expression is reduced. MicroRNA-122 (miR-122), a target of current phase II anti-HCV drugs, is known to protect HCV transcripts against XRNs. We show that HCV replication is less dependent on miR-122 in cells lacking DUSP11. Combined, these results implicate DUSP11 as an important component of XRN-mediated restriction of HCV.


Asunto(s)
Ácido Anhídrido Hidrolasas/metabolismo , Fosfatasas de Especificidad Dual/metabolismo , Exorribonucleasas/metabolismo , Hepacivirus/patogenicidad , Interacciones Huésped-Patógeno/fisiología , MicroARNs/metabolismo , Ácido Anhídrido Hidrolasas/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/virología , Línea Celular Tumoral , Fosfatasas de Especificidad Dual/genética , Exorribonucleasas/genética , Técnicas de Inactivación de Genes , Genoma Viral , Hepacivirus/fisiología , Hepatitis C Crónica/genética , Hepatitis C Crónica/virología , Hepatocitos/virología , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/virología , ARN Interferente Pequeño/metabolismo , ARN Viral/metabolismo , Replicación Viral/genética
12.
PLoS Pathog ; 14(7): e1007156, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-30048533

RESUMEN

MicroRNAs (miRNAs) are small RNAs that regulate diverse biological processes including multiple aspects of the host-pathogen interface. Consequently, miRNAs are commonly encoded by viruses that undergo long-term persistent infection. Papillomaviruses (PVs) are capable of undergoing persistent infection, but as yet, no widely-accepted PV-encoded miRNAs have been described. The incomplete understanding of PV-encoded miRNAs is due in part to lack of tractable laboratory models for most PV types. To overcome this, we have developed miRNA Discovery by forced Genome Expression (miDGE), a new wet bench approach to miRNA identification that screens numerous pathogen genomes in parallel. Using miDGE, we screened over 73 different PV genomes for the ability to code for miRNAs. Our results show that most PVs are unlikely to code for miRNAs and we conclusively demonstrate a lack of PV miRNA expression in cancers associated with infections of several high risk HPVs. However, we identified five different high-confidence or highly probable miRNAs encoded by four different PVs (Human PVs 17, 37, 41 and a Fringilla coelebs PV (FcPV1)). Extensive in vitro assays confirm the validity of these miRNAs in cell culture and two FcPV1 miRNAs are further confirmed to be expressed in vivo in a natural host. We show that miRNAs from two PVs (HPV41 & FcPV1) are able to regulate viral transcripts corresponding to the early region of the PV genome. Combined, these findings identify the first canonical PV miRNAs and support that miRNAs of either host or viral origin are important regulators of the PV life cycle.


Asunto(s)
Perfilación de la Expresión Génica/métodos , Regulación Viral de la Expresión Génica/genética , MicroARNs/genética , Papillomaviridae/genética , ARN Viral/análisis , Células HEK293 , Humanos , Infecciones por Papillomavirus/genética , ARN Viral/genética , Transcriptoma
13.
J Virol ; 92(16)2018 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-29875236

RESUMEN

Polyomaviruses (PyVs) can cause serious disease in immunosuppressed hosts. Several pathogenic PyVs encode microRNAs (miRNAs), small RNAs that regulate gene expression via RNA silencing. Despite recent advances in understanding the activities of PyV miRNAs, the biological functions of PyV miRNAs during in vivo infections are mostly unknown. The studies presented here used murine polyomavirus (MuPyV) as a model to assess the roles of the PyV miRNAs in a natural host. This analysis revealed that a MuPyV mutant that is unable to express miRNAs has enhanced viral DNA loads in select tissues at late times after infection. This is consistent with the PyV miRNAs functioning to reduce viral replication during the persistent phase of infection in a natural host. Additionally, the MuPyV miRNA locus promotes viruria during the acute phase of infection as evidenced by a defect in shedding during infection with the miRNA mutant virus. The viruria defect of the miRNA mutant virus could be rescued by infecting Rag2-/- mice. These findings implicate the miRNA locus as functioning in both the persistent and acute phases of infection and suggest a role for MuPyV miRNA in evading the adaptive immune response.IMPORTANCE MicroRNAs are expressed by diverse viruses, but for only a few is there any understanding of their in vivo function. PyVs can cause serious disease in immunocompromised hosts. Therefore, increased knowledge of how these viruses interact with the immune response is of clinical relevance. Here we show a novel activity for a viral miRNA locus in promoting virus shedding. This work indicates that in addition to any role for the PyV miRNA locus in long-term persistence, it also has biological activity during the acute phase. As this mutant phenotype is alleviated by infection of mice lacking an adaptive immune response, our work also connects the in vivo activity of the PyV miRNA locus to the immune response. Given that PyV-associated disease is associated with alterations in the immune response, our findings help to better understand how the balance between PyVs and the immune response becomes altered in pathogenic states.


Asunto(s)
MicroARNs/metabolismo , Infecciones por Polyomavirus/patología , Infecciones por Polyomavirus/virología , Poliomavirus/patogenicidad , ARN Viral/metabolismo , Orina/virología , Animales , Ratones , MicroARNs/genética , Poliomavirus/genética , ARN Viral/genética , Esparcimiento de Virus
14.
Virology ; 513: 180-187, 2018 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-29096160

RESUMEN

Mouse mammary tumor virus (MMTV) induces breast cancer in mice in the absence of known virally-encoded oncogenes. Tumorigenesis by MMTV is thought to occur primarily through insertional mutagenesis, leading to the activation of cellular proto-oncogenes and outgrowth of selected cells. Here we investigated whether MMTV encodes microRNAs (miRNAs) and/or modulates host miRNAs that could contribute to tumorigenesis. High throughput small RNA sequencing analysis of MMTV-infected cells and MMTV-induced mammary tumors demonstrates that MMTV does not encode miRNAs. However, infected tissues have altered levels of several host miRNAs, including increased expression of members of the oncogenic miRNA cluster, miR-17-92. Notably, similar changes in miRNA levels have been previously reported in human breast cancers. Combined, our results demonstrate that virally encoded miRNAs do not contribute to MMTV-mediated tumorigenesis, but that changes in specific host miRNAs in infected cells may contribute to virus replication and tumor biology.


Asunto(s)
Regulación de la Expresión Génica , Interacciones Huésped-Patógeno , Neoplasias Mamarias Experimentales/virología , Virus del Tumor Mamario del Ratón/fisiología , MicroARNs/análisis , Animales , Secuenciación de Nucleótidos de Alto Rendimiento , Ratones
15.
Nucleic Acids Res ; 45(17): e154, 2017 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-28973449

RESUMEN

Short hairpin RNAs (shRNAs) are effective in generating stable repression of gene expression. RNA polymerase III (RNAP III) type III promoters (U6 or H1) are typically used to drive shRNA expression. While useful for some knockdown applications, the robust expression of U6/H1-driven shRNAs can induce toxicity and generate heterogeneous small RNAs with undesirable off-target effects. Additionally, typical U6/H1 promoters encompass the majority of the ∼270 base pairs (bp) of vector space required for shRNA expression. This can limit the efficacy and/or number of delivery vector options, particularly when delivery of multiple gene/shRNA combinations is required. Here, we develop a compact shRNA (cshRNA) expression system based on retroviral microRNA (miRNA) gene architecture that uses RNAP III type II promoters. We demonstrate that cshRNAs coded from as little as 100 bps of total coding space can precisely generate small interfering RNAs (siRNAs) that are active in the RNA-induced silencing complex (RISC). We provide an algorithm with a user-friendly interface to design cshRNAs for desired target genes. This cshRNA expression system reduces the coding space required for shRNA expression by >2-fold as compared to the typical U6/H1 promoters, which may facilitate therapeutic RNAi applications where delivery vector space is limiting.


Asunto(s)
Marcación de Gen/métodos , Virus de la Leucemia Bovina/genética , MicroARNs/genética , ARN Polimerasa III/genética , ARN Interferente Pequeño/genética , ARN Viral/genética , Algoritmos , Emparejamiento Base , Secuencia de Bases , Regulación de la Expresión Génica , Silenciador del Gen , Genes Reporteros , Vectores Genéticos , Células HEK293 , Humanos , Virus de la Leucemia Bovina/metabolismo , Luciferasas/genética , Luciferasas/metabolismo , MicroARNs/metabolismo , Regiones Promotoras Genéticas , ARN Polimerasa III/metabolismo , ARN Interferente Pequeño/metabolismo , ARN Viral/metabolismo , Complejo Silenciador Inducido por ARN/genética , Complejo Silenciador Inducido por ARN/metabolismo , Análisis de Secuencia de ARN , Interfaz Usuario-Computador
16.
RNA Biol ; 14(11): 1457-1465, 2017 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-28296624

RESUMEN

Dual-specificity phosphatase 11 (DUSP11) is a conserved protein tyrosine phosphatase (PTP) in metazoans. The cellular substrates and physiologic activities of DUSP11 remain largely unknown. In nematodes, DUSP11 is required for normal development and RNA interference against endogenous RNAs (endo-RNAi) via molecular mechanisms that are not well understood. However, mammals lack analogous endo-RNAi pathways and consequently, a role for DUSP11 in mammalian RNA silencing was unanticipated. Recent work from our laboratory demonstrated that DUSP11 activity alters the silencing potential of noncanonical viral miRNAs in mammalian cells. Our studies further uncovered direct cellular substrates of DUSP11 and suggest that DUSP11 is part of regulatory pathway that controls the abundance of select triphosphorylated noncoding RNAs. Here, we highlight recent findings and present new data that advance understanding of mammalian DUSP11 during gene silencing and discuss the emerging biological activities of DUSP11 in mammalian cells.


Asunto(s)
Fosfatasas de Especificidad Dual/genética , Interacciones Huésped-Patógeno/genética , MicroARNs/genética , ARN Interferente Pequeño/genética , ARN Viral/genética , Animales , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Caenorhabditis elegans , ARN Helicasas DEAD-box/genética , ARN Helicasas DEAD-box/metabolismo , Fosfatasas de Especificidad Dual/metabolismo , Regulación de la Expresión Génica , Humanos , MicroARNs/metabolismo , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , ARN Polimerasa III/genética , ARN Polimerasa III/metabolismo , ARN Interferente Pequeño/metabolismo , ARN Viral/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Complejo Silenciador Inducido por ARN/genética , Complejo Silenciador Inducido por ARN/metabolismo , Ribonucleasa III/genética , Ribonucleasa III/metabolismo , Transducción de Señal , Virus/genética , Virus/metabolismo
17.
Genes Dev ; 30(18): 2076-2092, 2016 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-27798849

RESUMEN

RNA silencing is a conserved eukaryotic gene expression regulatory mechanism mediated by small RNAs. In Caenorhabditis elegans, the accumulation of a distinct class of siRNAs synthesized by an RNA-dependent RNA polymerase (RdRP) requires the PIR-1 phosphatase. However, the function of PIR-1 in RNAi has remained unclear. Since mammals lack an analogous siRNA biogenesis pathway, an RNA silencing role for the mammalian PIR-1 homolog (dual specificity phosphatase 11 [DUSP11]) was unexpected. Here, we show that the RNA triphosphatase activity of DUSP11 promotes the RNA silencing activity of viral microRNAs (miRNAs) derived from RNA polymerase III (RNAP III) transcribed precursors. Our results demonstrate that DUSP11 converts the 5' triphosphate of miRNA precursors to a 5' monophosphate, promoting loading of derivative 5p miRNAs into Argonaute proteins via a Dicer-coupled 5' monophosphate-dependent strand selection mechanism. This mechanistic insight supports a likely shared function for PIR-1 in C. elegans Furthermore, we show that DUSP11 modulates the 5' end phosphate group and/or steady-state level of several host RNAP III transcripts, including vault RNAs and Alu transcripts. This study shows that steady-state levels of select noncoding RNAs are regulated by DUSP11 and defines a previously unknown portal for small RNA-mediated silencing in mammals, revealing that DUSP11-dependent RNA silencing activities are shared among diverse metazoans.


Asunto(s)
Proteínas Argonautas/metabolismo , Fosfatasas de Especificidad Dual/genética , Fosfatasas de Especificidad Dual/metabolismo , MicroARNs/metabolismo , ARN no Traducido/metabolismo , Ácido Anhídrido Hidrolasas/metabolismo , Adenoviridae/genética , Técnicas de Inactivación de Genes , Células HEK293 , Humanos , Virus de la Leucemia Bovina/genética , Fosforilación , ARN Polimerasa III/metabolismo , ARN Viral/metabolismo
18.
mSphere ; 1(2)2016.
Artículo en Inglés | MEDLINE | ID: mdl-27301787

RESUMEN

Despite increasing interest in the biology of noncoding RNAs (ncRNAs), few functions have been uncovered for viral ncRNAs in vivo. In their recent article in mSphere, Feldman and colleagues [E. R. Feldman et al., mSphere 1(2):e00105-15, 2016, doi:10.1128/mSphere.00105-15] demonstrate a highly specific activity of a gammaherpesviral ncRNA in viral dissemination and establishment of latent infection. Their work highlights several interesting features that should be informative to future studies of viral ncRNA.

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