Fast evolution of SARS-CoV-2 driven by deamination systems in hosts

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is a positive-strand RNA virus that causes severe respiratory syndrome in humans, which is now referred to as coronavirus disease 2019 (COVID-19). Since December 2019, the new pathogen has rapidly spread globally, with over 65 million cases reported to the beginning of December 2020, including over 1.5 million deaths. Unfortunately, currently, there is no specific and effective treatment for COVID-19. As SARS-CoV-2 relies on its spike proteins (S) to bind to a host cell-surface receptor angiotensin-converting enzyme-2(ACE2), and this interaction is proved to be responsible for entering a virus into host cells, it makes an ideal target for antiviral drug development. In this work, we design three very short peptides based on the ACE2 sequence/structure fragments, which may effectively bind to the receptor-binding domain (RBD) of S protein and may, in turn, disrupt the important virus-host protein–protein interactions, blocking early steps of SARS-CoV-2 infection. Two of our peptides bind to virus protein with affinity in nanomolar range, and as very short peptides have great potential for drug development.

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Identifying SARS-CoV-2 Antiviral Compounds by Screening for Small Molecule Inhibitors of Nsp12/7/8 RNA-dependent RNA Polymerase

10.1101/2021.04.07.438807 ◽

2021 ◽

Author(s):

Agustina P. Bertolin ◽

Florian Weissmann ◽

Jingkun Zeng ◽

Viktor Posse ◽

Jennifer C. Milligan ◽

...

Keyword(s):

Rna Polymerase ◽

Rna Virus ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Etiologic Agent ◽

Host Cells ◽

Rdrp Activity ◽

Chemical Library ◽

Rna Dependent Rna Polymerase

SummaryThe coronavirus disease 2019 (COVID-19) global pandemic has turned into the largest public health and economic crisis in recent history impacting virtually all sectors of society. There is a need for effective therapeutics to battle the ongoing pandemic. Repurposing existing drugs with known pharmacological safety profiles is a fast and cost-effective approach to identify novel treatments. The COVID-19 etiologic agent is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a single-stranded positive-sense RNA virus. Coronaviruses rely on the enzymatic activity of the replication-transcription complex (RTC) to multiply inside host cells. The RTC core catalytic component is the RNA-dependent RNA polymerase (RdRp) holoenzyme. The RdRp is one of the key druggable targets for CoVs due to its essential role in viral replication, high degree of sequence and structural conservation and the lack of homologs in human cells. Here, we have expressed, purified and biochemically characterised active SARS-CoV-2 RdRp complexes. We developed a novel fluorescence resonance energy transfer (FRET)-based strand displacement assay for monitoring SARS-CoV-2 RdRp activity suitable for a high-throughput format. As part of a larger research project to identify inhibitors for all the enzymatic activities encoded by SARS-CoV-2, we used this assay to screen a custom chemical library of over 5000 approved and investigational compounds for novel SARS-CoV-2 RdRp inhibitors. We identified 3 novel compounds (GSK-650394, C646 and BH3I-1) and confirmed suramin and suramin-like compounds as in vitro SARS-CoV-2 RdRp activity inhibitors. We also characterised the antiviral efficacy of these drugs in cell-based assays that we developed to monitor SARS-CoV-2 growth.

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Viral RNA at Two Stages of Reovirus Infection Is Required for the Induction of Necroptosis

Journal of Virology ◽

10.1128/jvi.02404-16 ◽

2017 ◽

Vol 91 (6) ◽

Cited By ~ 25

Author(s):

Angela K. Berger ◽

Bradley E. Hiller ◽

Deepti Thete ◽

Anthony J. Snyder ◽

Encarnacion Perez ◽

...

Keyword(s):

Cell Death ◽

Immune System ◽

Virus Infection ◽

De Novo ◽

Rna Virus ◽

Viral Rna ◽

Host Cells ◽

Type I ◽

Tissue Destruction ◽

Reovirus Infection

ABSTRACT Necroptosis, a regulated form of necrotic cell death, requires the activation of the RIP3 kinase. Here, we identify that infection of host cells with reovirus can result in necroptosis. We find that necroptosis requires sensing of the genomic RNA within incoming virus particles via cytoplasmic RNA sensors to produce type I interferon (IFN). While these events that occur prior to the de novo synthesis of viral RNA are required for the induction of necroptosis, they are not sufficient. The induction of necroptosis also requires late stages of reovirus infection. Specifically, efficient synthesis of double-stranded RNA (dsRNA) within infected cells is required for necroptosis. These data indicate that viral RNA interfaces with host components at two different stages of infection to induce necroptosis. This work provides new molecular details about events in the viral replication cycle that contribute to the induction of necroptosis following infection with an RNA virus. IMPORTANCE An appreciation of how cell death pathways are regulated following viral infection may reveal strategies to limit tissue destruction and prevent the onset of disease. Cell death following virus infection can occur by apoptosis or a regulated form of necrosis known as necroptosis. Apoptotic cells are typically disposed of without activating the immune system. In contrast, necroptotic cells alert the immune system, resulting in inflammation and tissue damage. While apoptosis following virus infection has been extensively investigated, how necroptosis is unleashed following virus infection is understood for only a small group of viruses. Here, using mammalian reovirus, we highlight the molecular mechanism by which infection with a dsRNA virus results in necroptosis.

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An overview of RNA virus-encoded microRNAs

ExRNA ◽

10.1186/s41544-019-0037-6 ◽

2019 ◽

Vol 1 (1) ◽

Cited By ~ 5

Author(s):

Xihan Li ◽

Xiaoping Zou

Keyword(s):

Gene Expression ◽

Gene Regulation ◽

Viral Replication ◽

Potential Role ◽

Rna Viruses ◽

Rna Virus ◽

Host Cells ◽

Basic Pattern ◽

Double Stranded Dna ◽

Non Coding Rnas

Abstract MicroRNAs (miRNAs) are a number of small non-coding RNAs playing a regulatory part in gene expression. Many virus-encoded miRNAs have been found, which manifests that viruses as well apply the basic pattern of gene regulation, however, mostly in viruses transcribed from double-stranded DNA genomes. It is still in dispute if RNA viruses could encode miRNAs because the excision of miRNA might result in the cleavage of viral RNA genome. We will focus on the miRNAs encoded by RNA virus and discuss their potential role in viral replication cycle and host cells.

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Symbiosis Comes of Age at the 10th Biennial Meeting of Wolbachia Researchers

Applied and Environmental Microbiology ◽

10.1128/aem.03071-18 ◽

2019 ◽

Vol 85 (8) ◽

Cited By ~ 4

Author(s):

Irene L. G. Newton ◽

Barton E. Slatko

Keyword(s):

Cell Biology ◽

Rna Virus ◽

Host Cells ◽

Human Pathogens ◽

Content Type ◽

New Science ◽

Successful Infection ◽

Filarial Nematodes ◽

Insect Populations ◽

Basic Biology

ABSTRACT Wolbachia pipientis is an alphaproteobacterial obligate intracellular microbe and arguably the most successful infection on our planet, colonizing 40% to 60% of insect species. Wolbachia spp. are also present in most, but not all, filarial nematodes, where they are obligate mutualists and are the targets for antifilarial drug discovery. Although Wolbachia spp. are related to important human pathogens, they do not infect mammals but instead are well known for their reproductive manipulations of insect populations, inducing the following phenotypes: male killing, feminization, parthenogenesis induction, and cytoplasmic incompatibility (CI). The most common of these, CI, results in a sperm-egg incompatibility and increases the relative fecundity of infected females in a population. In the last decade, Wolbachia spp. have also been shown to provide a benefit to insects, where the infection can inhibit RNA virus replication within the host. Wolbachia spp. cannot be cultivated outside host cells, and no genetic tools are available in the symbiont, limiting approaches available for their study. This means that many questions fundamental to our understanding of Wolbachia basic biology remained unknown for decades. The 10th biennial international Wolbachia conference, Wolbachia Evolution, Ecology, Genomics and Cell Biology: A Chronicle of the Most Ubiquitous Symbiont, was held on 17 to 22 June 2018 in Salem, MA. In this review, we highlight the new science presented at the meeting, link it to prior efforts to answer these questions across the Wolbachia genus, and present the importance of these findings to the field of symbiosis. The topics covered in this review are based on the presentations at the conference.

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Increase of SARS-CoV 3CL peptidase activity due to macromolecular crowding effects in the milieu composition

Biological Chemistry ◽

10.1515/bc.2010.145 ◽

2010 ◽

Vol 391 (12) ◽

Cited By ~ 10

Author(s):

Debora N. Okamoto ◽

Lilian C.G. Oliveira ◽

Marcia Y. Kondo ◽

Maria H.S. Cezari ◽

Zoltán Szeltner ◽

...

Keyword(s):

Rna Virus ◽

Antiviral Agents ◽

Fine Tuning ◽

Host Cells ◽

Respiratory Syndrome Virus ◽

Peptidase Activity ◽

Buffer Solutions ◽

Tuning Mechanism ◽

Positive Strand Rna Virus ◽

Positive Strand Rna

Abstract The 3C-like peptidase of the severe acute respiratory syndrome virus (SARS-CoV) is strictly required for viral replication, thus being a potential target for the development of antiviral agents. In contrast to monomeric picornavirus 3C peptidases, SARS-CoV 3CLpro exists in equilibrium between the monomer and dimer forms in solution, and only the dimer is proteolytically active in dilute buffer solutions. In this study, the increase of SARS-CoV 3CLpro peptidase activity in presence of kosmotropic salts and crowding agents is described. The activation followed the Hofmeister series of anions, with two orders of magnitude enhancement in the presence of Na2SO4, whereas the crowding agents polyethylene glycol and bovine serum albumin increased the hydrolytic rate up to 3 times. Kinetic determinations of the monomer dimer dissociation constant (K d) indicated that activation was a result of a more active dimer, without significant changes in K d values. The activation was found to be independent of substrate length and was derived from both k cat increase and K m decrease. The viral peptidase activation described here could be related to the crowded intracellular environment and indicates a further fine-tuning mechanism for biological control, particularly in the microenvironment of the vesicles that are induced in host cells during positive strand RNA virus infection.

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Role of an Internal and Two 3′-Terminal RNA Elements in Assembly of Tombusvirus Replicase

Journal of Virology ◽

10.1128/jvi.79.16.10608-10618.2005 ◽

2005 ◽

Vol 79 (16) ◽

pp. 10608-10618 ◽

Cited By ~ 96

Author(s):

Zivile Panaviene ◽

Tadas Panavas ◽

Peter D. Nagy

Keyword(s):

Rna Virus ◽

Viral Rna ◽

Host Cells ◽

Replication Proteins ◽

Rna Sequences ◽

Alternative Structures ◽

Recognition Element ◽

Rna Elements

ABSTRACT Plus-strand RNA virus replication requires the assembly of the viral replicase complexes on intracellular membranes in the host cells. The replicase of Cucumber necrosis virus (CNV), a tombusvirus, contains the viral p33 and p92 replication proteins and possible host factors. In addition, the assembly of CNV replicase is stimulated in the presence of plus-stranded viral RNA (Z. Panaviene et al., J. Virol. 78:8254-8263, 2004). To define cis-acting viral RNA sequences that stimulate replicase assembly, we performed a systematic deletion approach with a model tombusvirus replicon RNA in Saccharomyces cerevisiae, which also coexpressed p33 and p92 replication proteins. In vitro replicase assays performed with purified CNV replicase preparations from yeast revealed critical roles for three RNA elements in CNV replicase assembly: the internal p33 recognition element (p33RE), the replication silencer element (RSE), and the 3′-terminal minus-strand initiation promoter (gPR). Deletion or mutagenesis of these elements reduced the activity of the CNV replicase to a minimal level. In addition to the primary sequences of gPR, RSE, and p33RE, formation of two alternative structures among these elements may also play a role in replicase assembly. Altogether, the role of multiple RNA elements in tombusvirus replicase assembly could be an important factor to ensure fidelity of template selection during replication.

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Seneca Valley virus intercellular transmission mediated by exosomes

10.1101/2020.02.14.950345 ◽

2020 ◽

Author(s):

Keshan Zhang ◽

Guowei Xu ◽

Shouxing Xu ◽

Xijuan Shi ◽

Chaochao Shen ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Clinical Symptoms ◽

Rna Virus ◽

Virus Transmission ◽

Foot And Mouth Disease ◽

Host Cells ◽

Productive Infection ◽

Infected Cells ◽

Seneca Valley Virus ◽

Positive Strand Rna

ABSTRACTExosomes are cup-shaped vesicles that are secreted by cells and are involved in the intercellular transport of a variety of substances, including proteins, RNA, and liposomes. Studies have shown that pathogenic microorganisms are contained in exosomes extracted from pathogenic micro-infected cells. The Seneca Valley virus (SVV) is a non-encapsulated single-stranded positive-strand RNA virus that causes ulceration in the pig’s nose, the appearance of blisters, and other clinical symptoms similar to foot-and-mouth disease (FMD). Whether exosomes from SVV-infected cells can mediate SVV intercellular transmission is of great significance. There have been no studies showing whether exosomes can carry SVV in susceptible and non-susceptible cells. Here, we first extracted and identified exosomes from SVV-infected IBRS-2 cells. It was confirmed that replication of SVV can be inhibited when IBRS-2 cells treated with exosomes inbihitor GW4869. Furthermore, laser confocal microscopy and qRT-PCR experiments were performed to investigate whether exosomes can carry SVV and enable the virus to proliferate in susceptible and non-susceptible cells. Finally, exosome-mediated intercellular transmission can not be completely blocked by SVV-specific neutralizing antibodies. Taken together, this study showed that exosomes extracted from the SVV-infected IBRS-2 cells can carry SVV and transmit productive SVV infection between SVV susceptible and non-susceptible cells, this transmit infection is resistant to SVV specific neutralization antibody.IMPORTANCEExosomes participate in intercellular communnication between cells. Exosomes derived from virus-infected cells can mediate virus transmission or/and regulate immune response. However, the function of exosomes that from SVV-infected host cells during SVV transmission is unclear. Here, we demonstrate SVV can utilize host exosomes to establish productive infection in intercellular transmission. Furthermore, exosome-mediated SVV transmission is resistant to SVVV-specific neutralizing antibodies. This discovery sheds light on neutralizing antibodies resistant to SVVV transmission by exosomes as a potential immune evasion mechanism.

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Deficient DNA mismatch repair and persistence of SARS-CoV-2 RNA shedding: a case report of hereditary nonpolyposis colorectal cancer with COVID-19 infection

BMC Infectious Diseases ◽

10.1186/s12879-021-06500-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Farzana Haque ◽

Patrick Lillie ◽

Farhana Haque ◽

Anthony Maraveyas

Keyword(s):

Colorectal Cancer ◽

Lynch Syndrome ◽

Mismatch Repair ◽

Hereditary Nonpolyposis Colorectal Cancer ◽

Rna Virus ◽

Genetic Mutation ◽

Host Cells ◽

Nasopharyngeal Swab ◽

Viral Shedding ◽

Hereditary Nonpolyposis

Abstract Background Several independent risk factors have been reported to influence viral shedding following COVID-19 infection, but the influence of host-related molecular factors has not yet been described. We report a case of a cancer patient with Lynch syndrome (hereditary nonpolyposis colorectal cancer, HNPCC) who manifested SARS-CoV-2 PCR (polymerase chain reaction) positivity for at least 54 days after contracting mild COVID-19 illness. We propose that deficient mismatch repair (MMR) may play a role in the prolonged SARS-CoV-2 RNA shedding. Case presentation A patient with Lynch syndrome was under surveillance for metastatic adenocarcinoma after completing palliative chemotherapy in October 2019. Between the period of April 2020 to June 2020, he was admitted multiple times to address several clinical needs mainly related to his underlying malignancy. These included progressive disease observed in the aortocaval lymph nodes leading to recurrent episodes of upper gastrointestinal bleeding, dehydration resulting in acute kidney injury and a short-lived episode of pyrexia. A SARS-CoV-2 PCR of the nasopharyngeal swab (NPS) was positive at his initial admission with mild COVID-19 symptoms. He remained positive on subsequent admissions when tested routinely for SARS-CoV-2 without demonstrating any apparent clinical features of COVID-19 infection. The MMR pathway, a component of DNA damage response (DDR), is impaired in Lynch syndrome due to an inherited genetic mutation. This pathway is also required for viral clearance from the host cells following certain RNA viral infections like influenza virus and other coronaviridae. Here we provide a current understanding of the importance of DDR deficiencies in the clearance of RNA virus and suggest how this may play a similar role in the clearance of COVID-19, as evident in our case that demonstrated persistent positivity. Conclusion The importance of understanding the scientific basis of extended viral shedding during the COVID-19 pandemic is now centre-stage in the establishment of robust track and trace services to allow the recovery and function of societies and economies. This patient with Lynch syndrome recovered from infection but had prolonged viral positivity, which might merit further investigation to better understand the effect of this condition on infection duration and outcome.

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Potentially translated sequences determine protein-coding potential of RNAs in cellular organisms

10.1101/2021.04.14.439730 ◽

2021 ◽

Author(s):

Yusuke Suenaga ◽

Mamoru Kato ◽

Momoko Nagai ◽

Kazuma Nakatani ◽

Hiroyuki Kogashi ◽

...

Keyword(s):

Noncoding Rna ◽

Rna Virus ◽

Host Cells ◽

Rna Sequences ◽

Protein Coding ◽

Functional Peptides ◽

Definition Of ◽

Virus Genomes ◽

Sequence Characteristics ◽

Coding Potential

AbstractRNA sequence characteristics determine whether their transcripts are coding or noncoding. Recent studies have shown that, paradoxical to the definition of noncoding RNA, several long noncoding RNAs (lncRNAs) translate functional peptides/proteins. However, the characteristics of RNA sequences that distinguish such newly identified coding transcripts from lncRNAs remain largely unknown. In this study, we found that potentially translated sequences in RNAs determine the protein-coding potential of RNAs in cellular organisms. We defined the potentially translated island (PTI) score as the fraction of the length of the longest potentially translated region among all regions. To analyze its relationship with protein-coding potential, we calculated the PTI scores in 3.4 million RNA transcripts from 100 cellular organisms, including 5 bacteria, 10 archaea, and 85 eukaryotes, as well as 105 positive-sense single-strand RNA virus genomes. In bacteria and archaea, coding and noncoding transcripts exclusively presented high and low PTI scores, respectively, whereas those of eukaryotic coding and noncoding transcripts showed relatively broader distributions. The relationship between the PTI score and protein-coding potential was sigmoidal in most eukaryotes; however, it was linear passing through the origin in three distinct eutherian lineages, including humans. The RNA sequences of virus genomes appeared to adapt to translation systems of host organisms by maximizing protein-coding potential in host cells. Hence, the PTIs determined the protein-coding potential of RNAs in cellular organisms. Additionally, coding and noncoding RNA do not exhibit dichotomous sequence characteristics in eukaryotes, instead they exhibit a gradient of protein-coding potential.

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