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1.
PLoS Pathog ; 17(1): e1009233, 2021 01.
Article in English | MEDLINE | ID: covidwho-1040062

ABSTRACT

The spike (S) protein of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) binds to a host cell receptor which facilitates viral entry. A polybasic motif detected at the cleavage site of the S protein has been shown to broaden the cell tropism and transmissibility of the virus. Here we examine the properties of SARS-CoV-2 variants with mutations at the S protein cleavage site that undergo inefficient proteolytic cleavage. Virus variants with S gene mutations generated smaller plaques and exhibited a more limited range of cell tropism compared to the wild-type strain. These alterations were shown to result from their inability to utilize the entry pathway involving direct fusion mediated by the host type II transmembrane serine protease, TMPRSS2. Notably, viruses with S gene mutations emerged rapidly and became the dominant SARS-CoV-2 variants in TMPRSS2-deficient cells including Vero cells. Our study demonstrated that the S protein polybasic cleavage motif is a critical factor underlying SARS-CoV-2 entry and cell tropism. As such, researchers should be alert to the possibility of de novo S gene mutations emerging in tissue-culture propagated virus strains.


Subject(s)
/genetics , Serine Endopeptidases/deficiency , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , Animals , Caco-2 Cells , Cell Line , Chlorocebus aethiops , HEK293 Cells , Humans , Mutation , /growth & development , Sequence Alignment , Serial Passage , Vero Cells , Viral Tropism
2.
Infect Genet Evol ; 88: 104708, 2021 03.
Article in English | MEDLINE | ID: covidwho-1039486

ABSTRACT

The pandemic due to novel coronavirus, SARS-CoV-2 is a serious global concern now. More than thousand new COVID-19 infections are getting reported daily for this virus across the globe. Thus, the medical research communities are trying to find the remedy to restrict the spreading of this virus, while the vaccine development work is still under research in parallel. In such critical situation, not only the medical research community, but also the scientists in different fields like microbiology, pharmacy, bioinformatics and data science are also sharing effort to accelerate the process of vaccine development, virus prediction, forecasting the transmissible probability and reproduction cases of virus for social awareness. With the similar context, in this article, we have studied sequence variability of the virus primarily focusing on three aspects: (a) sequence variability among SARS-CoV-1, MERS-CoV and SARS-CoV-2 in human host, which are in the same coronavirus family, (b) sequence variability of SARS-CoV-2 in human host for 54 different countries and (c) sequence variability between coronavirus family and country specific SARS-CoV-2 sequences in human host. For this purpose, as a case study, we have performed topological analysis of 2391 global genomic sequences of SARS-CoV-2 in association with SARS-CoV-1 and MERS-CoV using an integrated semi-alignment based computational technique. The results of the semi-alignment based technique are experimentally and statistically found similar to alignment based technique and computationally faster. Moreover, the outcome of this analysis can help to identify the nations with homogeneous SARS-CoV-2 sequences, so that same vaccine can be applied to their heterogeneous human population.


Subject(s)
/epidemiology , Coronavirus Infections/epidemiology , Genetic Variation , Genome, Viral , Pandemics , Severe Acute Respiratory Syndrome/epidemiology , Africa/epidemiology , Americas/epidemiology , Asia/epidemiology , Australia/epidemiology , Base Sequence , /virology , Computational Biology/methods , Coronavirus Infections/transmission , Coronavirus Infections/virology , Europe/epidemiology , Host-Pathogen Interactions/genetics , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/pathogenicity , SARS Virus/genetics , SARS Virus/pathogenicity , Sequence Alignment , Severe Acute Respiratory Syndrome/transmission , Severe Acute Respiratory Syndrome/virology
3.
Viruses ; 13(1)2021 Jan 16.
Article in English | MEDLINE | ID: covidwho-1031173

ABSTRACT

Our recent study identified seven key microRNAs (miR-8066, 5197, 3611, 3934-3p, 1307-3p, 3691-3p, 1468-5p) similar between SARS-CoV-2 and the human genome, pointing at miR-related mechanisms in viral entry and the regulatory effects on host immunity. To identify the putative roles of these miRs in zoonosis, we assessed their conservation, compared with humans, in some key wild and domestic animal carriers of zoonotic viruses, including bat, pangolin, pig, cow, rat, and chicken. Out of the seven miRs under study, miR-3611 was the most strongly conserved across all species; miR-5197 was the most conserved in pangolin, pig, cow, bat, and rat; miR-1307 was most strongly conserved in pangolin, pig, cow, bat, and human; miR-3691-3p in pangolin, cow, and human; miR-3934-3p in pig and cow, followed by pangolin and bat; miR-1468 was most conserved in pangolin, pig, and bat; while miR-8066 was most conserved in pangolin and pig. In humans, miR-3611 and miR-1307 were most conserved, while miR-8066, miR-5197, miR-3334-3p and miR-1468 were least conserved, compared with pangolin, pig, cow, and bat. Furthermore, we identified that changes in the miR-5197 nucleotides between pangolin and human can generate three new miRs, with differing tissue distribution in the brain, lung, intestines, lymph nodes, and muscle, and with different downstream regulatory effects on KEGG pathways. This may be of considerable importance as miR-5197 is localized in the spike protein transcript area of the SARS-CoV-2 genome. Our findings may indicate roles for these miRs in viral-host co-evolution in zoonotic hosts, particularly highlighting pangolin, bat, cow, and pig as putative zoonotic carriers, while highlighting the miRs' roles in KEGG pathways linked to viral pathogenicity and host responses in humans. This in silico study paves the way for investigations into the roles of miRs in zoonotic disease.


Subject(s)
Biological Coevolution , MicroRNAs/genetics , /genetics , Animals , /virology , Chickens , Gene Regulatory Networks , Genome/genetics , Host Specificity , Humans , Mammals , MicroRNAs/chemistry , MicroRNAs/metabolism , /physiology , Sequence Alignment , Tissue Distribution , Zoonoses/transmission , Zoonoses/virology
4.
Viruses ; 13(1)2020 12 30.
Article in English | MEDLINE | ID: covidwho-1004764

ABSTRACT

In 2019, a novel coronavirus, SARS-CoV-2/nCoV-19, emerged in Wuhan, China, and has been responsible for the current COVID-19 pandemic. The evolutionary origins of the virus remain elusive and understanding its complex mutational signatures could guide vaccine design and development. As part of the international "CoronaHack" in April 2020, we employed a collection of contemporary methodologies to compare the genomic sequences of coronaviruses isolated from human (SARS-CoV-2; n = 163), bat (bat-CoV; n = 215) and pangolin (pangolin-CoV; n = 7) available in public repositories. We have also noted the pangolin-CoV isolate MP789 to bare stronger resemblance to SARS-CoV-2 than other pangolin-CoV. Following de novo gene annotation prediction, analyses of gene-gene similarity network, codon usage bias and variant discovery were undertaken. Strong host-associated divergences were noted in ORF3a, ORF6, ORF7a, ORF8 and S, and in codon usage bias profiles. Last, we have characterised several high impact variants (in-frame insertion/deletion or stop gain) in bat-CoV and pangolin-CoV populations, some of which are found in the same amino acid position and may be highlighting loci of potential functional relevance.


Subject(s)
Biodiversity , Chiroptera/virology , Coronavirus/genetics , /genetics , Animals , Coronavirus/classification , Evolution, Molecular , Gene Regulatory Networks , Genome, Viral , Genomics , Host Specificity , Humans , Molecular Sequence Annotation , Phylogeny , Sequence Alignment
5.
Viruses ; 12(12)2020 12 21.
Article in English | MEDLINE | ID: covidwho-1000348

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current COVID-19 pandemic. The 3' untranslated region (UTR) of this ß-CoV contains essential cis-acting RNA elements for the viral genome transcription and replication. These elements include an equilibrium between an extended bulged stem-loop (BSL) and a pseudoknot. The existence of such an equilibrium is supported by reverse genetic studies and phylogenetic covariation analysis and is further proposed as a molecular switch essential for the control of the viral RNA polymerase binding. Here, we report the SARS-CoV-2 3' UTR structures in cells that transcribe the viral UTRs harbored in a minigene plasmid and isolated infectious virions using a chemical probing technique, namely dimethyl sulfate (DMS)-mutational profiling with sequencing (MaPseq). Interestingly, the putative pseudoknotted conformation was not observed, indicating that its abundance in our systems is low in the absence of the viral nonstructural proteins (nsps). Similarly, our results also suggest that another functional cis-acting element, the three-helix junction, cannot stably form. The overall architectures of the viral 3' UTRs in the infectious virions and the minigene-transfected cells are almost identical.


Subject(s)
3' Untranslated Regions/genetics , Nucleic Acid Conformation , Pandemics , RNA, Viral/genetics , /genetics , Animals , Base Sequence , Cell Line , Conserved Sequence , Cricetinae , High-Throughput Nucleotide Sequencing , Humans , Mesocricetus , Models, Molecular , Plasmids , Point Mutation , Reverse Genetics/methods , Sequence Alignment , Sequence Homology, Nucleic Acid , Sulfuric Acid Esters , Transcription, Genetic , Virion/genetics , Virion/physiology
6.
J Virol ; 94(22)2020 10 27.
Article in English | MEDLINE | ID: covidwho-982189

ABSTRACT

Coronaviruses (CoV) have caused a number of major epidemics in humans and animals, including the current pandemic of coronavirus disease 2019 (COVID-19), which has brought a renewed focus on the evolution and interspecies transmission of coronaviruses. Swine acute diarrhea syndrome coronavirus (SADS-CoV), which was recently identified in piglets in southern China, is an alphacoronavirus that originates from the same genus of horseshoe bats as severe acute respiratory syndrome CoV (SARS-CoV) and that was reported to be capable of infecting cells from a broad range of species, suggesting a considerable potential for interspecies transmission. Given the importance of the coronavirus spike (S) glycoprotein in host range determination and viral entry, we report a cryo-electron microscopy (cryo-EM) structure of the SADS-CoV S trimer in the prefusion conformation at a 3.55-Å resolution. Our structure reveals that the SADS-CoV S trimer assumes an intrasubunit quaternary packing mode in which the S1 subunit N-terminal domain (S1-NTD) and the S1 subunit C-terminal domain (S1-CTD) of the same protomer pack together by facing each other in the lying-down state. SADS-CoV S has several distinctive structural features that may facilitate immune escape, such as a relatively compact architecture of the S trimer and epitope masking by glycan shielding. Comparison of SADS-CoV S with the spike proteins of the other coronavirus genera suggested that the structural features of SADS-CoV S are evolutionarily related to those of the spike proteins of the other genera rather than to the spike protein of a typical alphacoronavirus. These data provide new insights into the evolutionary relationship between spike glycoproteins of SADS-CoV and those of other coronaviruses and extend our understanding of their structural and functional diversity.IMPORTANCE In this article, we report the atomic-resolution prefusion structure of the spike protein from swine acute diarrhea syndrome coronavirus (SADS-CoV). SADS-CoV is a pathogenic alphacoronavirus that was responsible for a large-scale outbreak of fatal disease in pigs and that was reported to be capable of interspecies transmission. We describe the overall structure of the SADS-CoV spike protein and conducted a detailed analysis of its main structural elements. Our results and analyses are consistent with those of previous phylogenetic studies and suggest that the SADS-CoV spike protein is evolutionarily related to the spike proteins of betacoronaviruses, with a strong similarity in S1-NTDs and a marked divergence in S1-CTDs. Moreover, we discuss the possible immune evasion strategies used by the SADS-CoV spike protein. Our study provides insights into the structure and immune evasion strategies of the SADS-CoV spike protein and broadens the understanding of the evolutionary relationships between coronavirus spike proteins of different genera.


Subject(s)
Alphacoronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/ultrastructure , Alphacoronavirus/genetics , Amino Acid Sequence , Cryoelectron Microscopy , Evolution, Molecular , Immune Evasion , Models, Molecular , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry , Structural Homology, Protein
7.
Genomics ; 113(1 Pt 1): 331-343, 2021 01.
Article in English | MEDLINE | ID: covidwho-972544

ABSTRACT

An outbreak, caused by an RNA virus, SARS-CoV-2 named COVID-19 has become pandemic with a magnitude which is daunting to all public health institutions in the absence of specific antiviral treatment. Surface glycoprotein and nucleocapsid phosphoprotein are two important proteins of this virus facilitating its entry into host cell and genome replication. Small interfering RNA (siRNA) is a prospective tool of the RNA interference (RNAi) pathway for the control of human viral infections by suppressing viral gene expression through hybridization and neutralization of target complementary mRNA. So, in this study, the power of RNA interference technology was harnessed to develop siRNA molecules against specific target genes namely, nucleocapsid phosphoprotein gene and surface glycoprotein gene. Conserved sequence from 139 SARS-CoV-2 strains from around the globe was collected to construct 78 siRNA that can inactivate nucleocapsid phosphoprotein and surface glycoprotein genes. Finally, based on GC content, free energy of folding, free energy of binding, melting temperature, efficacy prediction and molecular docking analysis, 8 siRNA molecules were selected which are proposed to exert the best action. These predicted siRNAs should effectively silence the genes of SARS-CoV-2 during siRNA mediated treatment assisting in the response against SARS-CoV-2.


Subject(s)
/therapy , Computational Chemistry , Drug Design , Genetic Therapy/methods , Molecular Docking Simulation , RNA Interference , RNA, Messenger/antagonists & inhibitors , RNA, Small Interfering/chemistry , RNA, Viral/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/genetics , Argonaute Proteins/chemistry , Argonaute Proteins/genetics , Base Composition , /virology , Evolution, Molecular , Gene Expression Regulation, Viral/drug effects , Humans , Pandemics , Phosphoproteins/genetics , Phylogeny , RNA Folding , RNA, Guide/chemistry , RNA, Guide/genetics , RNA, Messenger/genetics , RNA, Small Interfering/pharmacology , RNA, Small Interfering/therapeutic use , RNA, Viral/genetics , Sequence Alignment , Thermodynamics
8.
Viruses ; 12(10)2020 09 27.
Article in English | MEDLINE | ID: covidwho-908357

ABSTRACT

The transmission and evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are of paramount importance in controlling and combating the coronavirus disease 2019 (COVID-19) pandemic. Currently, over 15,000 SARS-CoV-2 single mutations have been recorded, which have a great impact on the development of diagnostics, vaccines, antibody therapies, and drugs. However, little is known about SARS-CoV-2's evolutionary characteristics and general trend. In this work, we present a comprehensive genotyping analysis of existing SARS-CoV-2 mutations. We reveal that host immune response via APOBEC and ADAR gene editing gives rise to near 65% of recorded mutations. Additionally, we show that children under age five and the elderly may be at high risk from COVID-19 because of their overreaction to the viral infection. Moreover, we uncover that populations of Oceania and Africa react significantly more intensively to SARS-CoV-2 infection than those of Europe and Asia, which may explain why African Americans were shown to be at increased risk of dying from COVID-19, in addition to their high risk of COVID-19 infection caused by systemic health and social inequities. Finally, our study indicates that for two viral genome sequences of the same origin, their evolution order may be determined from the ratio of mutation type, C > T over T > C.


Subject(s)
Betacoronavirus/genetics , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Evolution, Molecular , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Female , Gene Editing , Genome, Viral , Genotype , Host-Pathogen Interactions , Humans , Male , Mutation , Pandemics , Polymorphism, Single Nucleotide , Sequence Alignment , Viral Proteins/genetics
9.
J Virol ; 94(22)2020 10 27.
Article in English | MEDLINE | ID: covidwho-901267

ABSTRACT

Coronaviruses (CoV) have caused a number of major epidemics in humans and animals, including the current pandemic of coronavirus disease 2019 (COVID-19), which has brought a renewed focus on the evolution and interspecies transmission of coronaviruses. Swine acute diarrhea syndrome coronavirus (SADS-CoV), which was recently identified in piglets in southern China, is an alphacoronavirus that originates from the same genus of horseshoe bats as severe acute respiratory syndrome CoV (SARS-CoV) and that was reported to be capable of infecting cells from a broad range of species, suggesting a considerable potential for interspecies transmission. Given the importance of the coronavirus spike (S) glycoprotein in host range determination and viral entry, we report a cryo-electron microscopy (cryo-EM) structure of the SADS-CoV S trimer in the prefusion conformation at a 3.55-Å resolution. Our structure reveals that the SADS-CoV S trimer assumes an intrasubunit quaternary packing mode in which the S1 subunit N-terminal domain (S1-NTD) and the S1 subunit C-terminal domain (S1-CTD) of the same protomer pack together by facing each other in the lying-down state. SADS-CoV S has several distinctive structural features that may facilitate immune escape, such as a relatively compact architecture of the S trimer and epitope masking by glycan shielding. Comparison of SADS-CoV S with the spike proteins of the other coronavirus genera suggested that the structural features of SADS-CoV S are evolutionarily related to those of the spike proteins of the other genera rather than to the spike protein of a typical alphacoronavirus. These data provide new insights into the evolutionary relationship between spike glycoproteins of SADS-CoV and those of other coronaviruses and extend our understanding of their structural and functional diversity.IMPORTANCE In this article, we report the atomic-resolution prefusion structure of the spike protein from swine acute diarrhea syndrome coronavirus (SADS-CoV). SADS-CoV is a pathogenic alphacoronavirus that was responsible for a large-scale outbreak of fatal disease in pigs and that was reported to be capable of interspecies transmission. We describe the overall structure of the SADS-CoV spike protein and conducted a detailed analysis of its main structural elements. Our results and analyses are consistent with those of previous phylogenetic studies and suggest that the SADS-CoV spike protein is evolutionarily related to the spike proteins of betacoronaviruses, with a strong similarity in S1-NTDs and a marked divergence in S1-CTDs. Moreover, we discuss the possible immune evasion strategies used by the SADS-CoV spike protein. Our study provides insights into the structure and immune evasion strategies of the SADS-CoV spike protein and broadens the understanding of the evolutionary relationships between coronavirus spike proteins of different genera.


Subject(s)
Alphacoronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/ultrastructure , Alphacoronavirus/genetics , Amino Acid Sequence , Cryoelectron Microscopy , Evolution, Molecular , Immune Evasion , Models, Molecular , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry , Structural Homology, Protein
10.
Virology ; 552: 107-111, 2021 01 02.
Article in English | MEDLINE | ID: covidwho-899647

ABSTRACT

Nisin, a food-grade antimicrobial peptide produced by lactic acid bacteria has been examined for its probable interaction with the human ACE2 (hACE2) receptor, the site where spike protein of SARS-CoV-2 binds. Among the eight nisin variants examined, nisin H, nisin Z, nisin U and nisin A showed a significant binding affinity towards hACE2, higher than that of the RBD (receptor binding domain) of the SARS-CoV-2 spike protein. The molecular interaction of nisin with hACE2 was investigated by homology modeling and docking studies. Further, binding efficiency of the most potent nisin H was evaluated through the interaction of hACE2:nisin H complex with RBD (receptor-binding domain) of SARS-CoV-2 and that of hACE2:RBD complex with nisin H. Here, nisin H acted as a potential competitor of RBD to access the hACE2 receptor. The study unravels for the first time that a globally used food preservative, nisin has the potential to bind to hACE2.


Subject(s)
/metabolism , Nisin/metabolism , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence , Binding Sites , Humans , Models, Molecular , Molecular Docking Simulation , Nisin/chemistry , Protein Binding , Protein Domains , Receptors, Virus/chemistry , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry
11.
mBio ; 11(6)2020 10 30.
Article in English | MEDLINE | ID: covidwho-894828

ABSTRACT

The ultimate outcome of the coronavirus disease 2019 (COVID-19) pandemic is unknown and is dependent on a complex interplay of its pathogenicity, transmissibility, and population immunity. In the current study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was investigated for the presence of large-scale internal RNA base pairing in its genome. This property, termed genome-scale ordered RNA structure (GORS) has been previously associated with host persistence in other positive-strand RNA viruses, potentially through its shielding effect on viral RNA recognition in the cell. Genomes of SARS-CoV-2 were remarkably structured, with minimum folding energy differences (MFEDs) of 15%, substantially greater than previously examined viruses such as hepatitis C virus (HCV) (MFED of 7 to 9%). High MFED values were shared with all coronavirus genomes analyzed and created by several hundred consecutive energetically favored stem-loops throughout the genome. In contrast to replication-associated RNA structure, GORS was poorly conserved in the positions and identities of base pairing with other sarbecoviruses-even similarly positioned stem-loops in SARS-CoV-2 and SARS-CoV rarely shared homologous pairings, indicative of more rapid evolutionary change in RNA structure than in the underlying coding sequences. Sites predicted to be base paired in SARS-CoV-2 showed less sequence diversity than unpaired sites, suggesting that disruption of RNA structure by mutation imposes a fitness cost on the virus that is potentially restrictive to its longer evolution. Although functionally uncharacterized, GORS in SARS-CoV-2 and other coronaviruses represents important elements in their cellular interactions that may contribute to their persistence and transmissibility.IMPORTANCE The detection and characterization of large-scale RNA secondary structure in the genome of SARS-CoV-2 indicate an extraordinary and unsuspected degree of genome structural organization; this could be effectively visualized through a newly developed contour plotting method that displays positions, structural features, and conservation of RNA secondary structure between related viruses. Such RNA structure imposes a substantial evolutionary cost; paired sites showed greater restriction in diversity and represent a substantial additional constraint in reconstructing its molecular epidemiology. Its biological relevance arises from previously documented associations between possession of structured genomes and persistence, as documented for HCV and several other RNA viruses infecting humans and mammals. Shared properties potentially conferred by large-scale structure in SARS-CoV-2 include increasing evidence for prolonged infections and induced immune dysfunction that prevents development of protective immunity. The findings provide an additional element to cellular interactions that potentially influences the natural history of SARS-CoV-2, its pathogenicity, and its transmission.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Coronavirus/genetics , Pneumonia, Viral/virology , RNA, Viral/chemistry , RNA, Viral/genetics , Animals , Base Sequence , Evolution, Molecular , Genome, Viral , Humans , Nucleic Acid Conformation , Pandemics , Sequence Alignment
12.
Commun Biol ; 3(1): 641, 2020 10 27.
Article in English | MEDLINE | ID: covidwho-894423

ABSTRACT

The emergence of SARS-CoV-2 has caused over a million human deaths and massive global disruption. The viral infection may also represent a threat to our closest living relatives, nonhuman primates. The contact surface of the host cell receptor, ACE2, displays amino acid residues that are critical for virus recognition, and variations at these critical residues modulate infection susceptibility. Infection studies have shown that some primate species develop COVID-19-like symptoms; however, the susceptibility of most primates is unknown. Here, we show that all apes and African and Asian monkeys (catarrhines), exhibit the same set of twelve key amino acid residues as human ACE2. Monkeys in the Americas, and some tarsiers, lemurs and lorisoids, differ at critical contact residues, and protein modeling predicts that these differences should greatly reduce SARS-CoV-2 binding affinity. Other lemurs are predicted to be closer to catarrhines in their susceptibility. Our study suggests that apes and African and Asian monkeys, and some lemurs, are likely to be highly susceptible to SARS-CoV-2. Urgent actions have been undertaken to limit the exposure of great apes to humans, and similar efforts may be necessary for many other primate species.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/veterinary , Host Specificity/genetics , Pandemics/veterinary , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/veterinary , Primate Diseases/enzymology , Primates/genetics , Receptors, Virus/genetics , Amino Acid Sequence , Amino Acid Substitution , Animals , Betacoronavirus/physiology , Biological Evolution , Chiroptera/genetics , Conserved Sequence , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Genetic Predisposition to Disease , Mammals/genetics , Models, Molecular , Mutation, Missense , Peptidyl-Dipeptidase A/chemistry , Phylogeny , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Point Mutation , Primate Diseases/virology , Protein Binding , Protein Conformation , Risk , Sequence Alignment , Sequence Homology, Amino Acid , Species Specificity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
13.
Avian Dis ; 64(2): 183-196, 2020 06.
Article in English | MEDLINE | ID: covidwho-892407

ABSTRACT

Nine infectious bronchitis virus (IBV) strains belonging to the GI-7 lineage were isolated between 2009 and 2017 in China. Phylogenetic analysis and comparisons of full-length sequences of the S1 gene suggested that the GI-7 lineage should be further classified as Taiwan (TW)-I and TW-II sublineages, which correspond to the previous TW-I and TW-II genotypes. The nine IBV strains were clustered in the TW-II sublineage. Further investigation revealed that viruses in the TW-I and TW-II were not only genetically but also antigenically different. Moreover, the TW-II sublineage contained various clades and recombinants. A recombinant was found to originate from recombination events between field strains (TW-II ck/CH/LJL/090608- and GI-19 ck/ CH/LDL/091022-like viruses) in which the recombination in the S1 subunit coding sequences had led to changes in antigenicity of the viruses. A more in-depth investigation demonstrated that TW-II viruses appear to have undergone a significant evolution following introduction in mainland China, which resulted in the viruses diverging into different clades. The viruses between the different clades in TW-II sublineage exhibited a significant change in genetic and antigenic characteristics. In addition, the five TW-II viruses selected on the basis of the results of S1 nucleotide sequence phylogenetic trees showed different pathogenicity to specific-pathogen-free chickens, although they could induce nephritis in the infected chickens and thus were identified as nephropathogenic strains.


Subject(s)
Chickens , Coronavirus Infections/veterinary , Infectious bronchitis virus , Poultry Diseases/virology , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , Animals , Antigens, Viral/genetics , Antigens, Viral/metabolism , China , Coronavirus Infections/virology , Infectious bronchitis virus/genetics , Infectious bronchitis virus/immunology , Infectious bronchitis virus/pathogenicity , Phylogeny , Sequence Alignment , Specific Pathogen-Free Organisms , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
14.
Euro Surveill ; 25(28)2020 07.
Article in English | MEDLINE | ID: covidwho-874407

ABSTRACT

BackgroundA novel coronavirus, SARS-CoV-2, which emerged at the end of 2019 and causes COVID-19, has resulted in worldwide human infections. While genetically distinct, SARS-CoV-1, the aetiological agent responsible for an outbreak of severe acute respiratory syndrome (SARS) in 2002-2003, utilises the same host cell receptor as SARS-CoV-2 for entry: angiotensin-converting enzyme 2 (ACE2). Parts of the SARS-CoV-1 spike glycoprotein (S protein), which interacts with ACE2, appear conserved in SARS-CoV-2.AimThe cross-reactivity with SARS-CoV-2 of monoclonal antibodies (mAbs) previously generated against the S protein of SARS-CoV-1 was assessed.MethodsThe SARS-CoV-2 S protein sequence was aligned to those of SARS-CoV-1, Middle East respiratory syndrome (MERS) and common-cold coronaviruses. Abilities of mAbs generated against SARS-CoV-1 S protein to bind SARS-CoV-2 or its S protein were tested with SARS-CoV-2 infected cells as well as cells expressing either the full length protein or a fragment of its S2 subunit. Quantitative ELISA was also performed to compare binding of mAbs to recombinant S protein.ResultsAn immunogenic domain in the S2 subunit of SARS-CoV-1 S protein is highly conserved in SARS-CoV-2 but not in MERS and human common-cold coronaviruses. Four murine mAbs raised against this immunogenic fragment could recognise SARS-CoV-2 S protein expressed in mammalian cell lines. In particular, mAb 1A9 was demonstrated to detect S protein in SARS-CoV-2-infected cells and is suitable for use in a sandwich ELISA format.ConclusionThe cross-reactive mAbs may serve as useful tools for SARS-CoV-2 research and for the development of diagnostic assays for COVID-19.


Subject(s)
Antibodies, Monoclonal/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Sequence , Animals , Betacoronavirus/genetics , Blotting, Western , COS Cells , Chlorocebus aethiops , Conserved Sequence , Coronavirus Infections/genetics , Coronavirus Infections/virology , Cross Reactions/immunology , Enzyme-Linked Immunosorbent Assay/methods , Fluorescent Antibody Technique/methods , Genome, Viral , Mice , Pandemics , Peptidyl-Dipeptidase A/immunology , Plasmids , Pneumonia, Viral/genetics , Recombinant Proteins/immunology , SARS Virus/genetics , Sequence Alignment , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/genetics , Transfection , Vero Cells , Virus Integration
15.
Biol Direct ; 15(1): 19, 2020 10 16.
Article in English | MEDLINE | ID: covidwho-874053

ABSTRACT

The spike glycoprotein of the SARS-CoV-2 virus, which causes COVID-19, has attracted attention for its vaccine potential and binding capacity to host cell surface receptors. Much of this research focus has centered on the ectodomain of the spike protein. The ectodomain is anchored to a transmembrane region, followed by a cytoplasmic tail. Here we report a distant sequence similarity between the cysteine-rich cytoplasmic tail of the coronavirus spike protein and the hepcidin protein that is found in humans and other vertebrates. Hepcidin is thought to be the key regulator of iron metabolism in humans through its inhibition of the iron-exporting protein ferroportin. An implication of this preliminary observation is to suggest a potential route of investigation in the coronavirus research field making use of an already-established literature on the interplay of local and systemic iron regulation, cytokine-mediated inflammatory processes, respiratory infections and the hepcidin protein. The question of possible homology and an evolutionary connection between the viral spike protein and hepcidin is not assessed in this report, but some scenarios for its study are discussed.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Hepcidins/genetics , Iron/metabolism , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/genetics , Animals , Cation Transport Proteins/metabolism , Cysteine/chemistry , Cytokines/metabolism , Cytoplasm/metabolism , Hepcidins/chemistry , Humans , Hypoxia , Inflammation , Interleukin-6/metabolism , Pandemics , Protein Domains , Protein Processing, Post-Translational , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry , Tetraodontiformes
16.
Viruses ; 12(1)2020 01 09.
Article in English | MEDLINE | ID: covidwho-830212

ABSTRACT

Porcine deltacoronavirus (PDCoV) is a porcine enteropathogenic coronavirus that causes watery diarrhea, vomiting, and frequently death in piglets, causing serious economic losses to the pig industry. The strain CHN-JS-2017 was isolated and identified by cytopathology, immunofluorescence assays, transmission electron microscopy, and sequence analysis. A nucleotide sequence alignment showed that the whole genome of CHN-JS-2017 is 97.4%-99.6% identical to other PDCoV strains. The pathogenicity of the CHN-JS-2017 strain was investigated in orally inoculated five-day-old piglets; the piglets developed acute, watery diarrhea, but all recovered and survived. CHN-JS-2017 infection-induced microscopic lesions were observed, and viral antigens were detected mainly by immunohistochemical staining in the small intestine. The neonatal Fc receptor (FcRn) and polymeric immunoglobulin receptor (pIgR) are crucial immunoglobulin (Ig) receptors for the transcytosis ofimmunoglobulin G (IgG), IgA, or IgM. Importantly, CHN-JS-2017 infected five-day-old piglets could significantly down-regulate the expression of FcRn, pIgR, and nuclear factor-kappa B (NF-κB)in the intestinal mucosa. Note that the level of FcRn mRNA in the intestinal mucosa of normal piglets is positively correlated with pIgR and NF-κB. At the same time, the expressions of FcRn, pIgR, and NF-κB mRNA are also positively correlated in infected piglets. These results may help explain the immunological and pathological changes associated with porcine deltacorononirus infection.


Subject(s)
Coronavirus Infections/veterinary , Coronavirus/classification , Histocompatibility Antigens Class I/immunology , Intestinal Mucosa/immunology , Receptors, Fc/immunology , Receptors, Polymeric Immunoglobulin/immunology , Swine Diseases/virology , Animals , Antigens, Viral/analysis , Coronavirus/isolation & purification , Coronavirus Infections/immunology , Diarrhea/veterinary , Diarrhea/virology , Gene Expression Regulation , Intestinal Mucosa/virology , Intestine, Small/immunology , Intestine, Small/virology , NF-kappa B/immunology , Phylogeny , RNA, Viral/analysis , Sequence Alignment , Sequence Analysis, DNA , Swine , Swine Diseases/immunology , Virus Shedding
17.
Biochem Biophys Res Commun ; 526(1): 165-169, 2020 05 21.
Article in English | MEDLINE | ID: covidwho-828037

ABSTRACT

SARS-CoV-2 causes the recent global COVID-19 public health emergency. ACE2 is the receptor for both SARS-CoV-2 and SARS-CoV. To predict the potential host range of SARS-CoV-2, we analyzed the key residues of ACE2 for recognizing S protein. We found that most of the selected mammals including pets (dog and cat), pangolin and Circetidae mammals remained the most of key residues for association with S protein from SARS-CoV and SARS-CoV-2. The interaction interface between cat/dog/pangolin/Chinese hamster ACE2 and SARS-CoV/SARS-CoV-2 S protein was simulated through homology modeling. We identified that N82 in ACE2 showed a closer contact with SARS-CoV-2 S protein than M82 in human ACE2. Our finding will provide important insights into the host range of SARS-CoV-2 and a new strategy to design an optimized ACE2 for SARS-CoV-2 infection.


Subject(s)
Betacoronavirus/physiology , Peptidyl-Dipeptidase A/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Viral Tropism , Amino Acid Sequence , Animals , Coronavirus Infections/metabolism , Coronavirus Infections/transmission , Coronavirus Infections/virology , Humans , Mammals/classification , Mammals/metabolism , Models, Molecular , Pandemics , Peptidyl-Dipeptidase A/chemistry , Pneumonia, Viral/metabolism , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry
19.
Biochem J ; 477(5): 1009-1019, 2020 03 13.
Article in English | MEDLINE | ID: covidwho-827308

ABSTRACT

Severe acute respiratory syndrome coronavirus is the causative agent of a respiratory disease with a high case fatality rate. During the formation of the coronaviral replication/transcription complex, essential steps include processing of the conserved polyprotein nsp7-10 region by the main protease Mpro and subsequent complex formation of the released nsp's. Here, we analyzed processing of the coronavirus nsp7-10 region using native mass spectrometry showing consumption of substrate, rise and fall of intermediate products and complexation. Importantly, there is a clear order of cleavage efficiencies, which is influenced by the polyprotein tertiary structure. Furthermore, the predominant product is an nsp7+8(2 : 2) hetero-tetramer with nsp8 scaffold. In conclusion, native MS, opposed to other methods, can expose the processing dynamics of viral polyproteins and the landscape of protein interactions in one set of experiments. Thereby, new insights into protein interactions, essential for generation of viral progeny, were provided, with relevance for development of antivirals.


Subject(s)
RNA-Binding Proteins/genetics , Sequence Alignment/methods , Viral Nonstructural Proteins/genetics , Viral Regulatory and Accessory Proteins/genetics , Coronavirus Infections/genetics , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Fluorescence Resonance Energy Transfer , Protein Structure, Secondary , RNA-Binding Proteins/chemistry , Viral Nonstructural Proteins/chemistry , Viral Regulatory and Accessory Proteins/chemistry , Virus Replication/physiology
20.
Elife ; 92020 10 01.
Article in English | MEDLINE | ID: covidwho-809713

ABSTRACT

Understanding the emergence of novel viruses requires an accurate and comprehensive annotation of their genomes. Overlapping genes (OLGs) are common in viruses and have been associated with pandemics but are still widely overlooked. We identify and characterize ORF3d, a novel OLG in SARS-CoV-2 that is also present in Guangxi pangolin-CoVs but not other closely related pangolin-CoVs or bat-CoVs. We then document evidence of ORF3d translation, characterize its protein sequence, and conduct an evolutionary analysis at three levels: between taxa (21 members of Severe acute respiratory syndrome-related coronavirus), between human hosts (3978 SARS-CoV-2 consensus sequences), and within human hosts (401 deeply sequenced SARS-CoV-2 samples). ORF3d has been independently identified and shown to elicit a strong antibody response in COVID-19 patients. However, it has been misclassified as the unrelated gene ORF3b, leading to confusion. Our results liken ORF3d to other accessory genes in emerging viruses and highlight the importance of OLGs.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Evolution, Molecular , Genes, Overlapping , Genes, Viral , Host Specificity/genetics , Open Reading Frames/genetics , Pandemics , Pneumonia, Viral/virology , Amino Acid Sequence , Animals , Antibodies, Viral/immunology , Antibody Specificity , Antigens, Viral/biosynthesis , Antigens, Viral/genetics , Antigens, Viral/immunology , Betacoronavirus/pathogenicity , Betacoronavirus/physiology , China/epidemiology , Chiroptera/virology , Coronavirus/genetics , Coronavirus Infections/epidemiology , Epitopes/genetics , Epitopes/immunology , Europe/epidemiology , Eutheria/virology , Gene Expression Regulation, Viral , Genetic Variation , Haplotypes/genetics , Humans , Models, Molecular , Mutation , Phylogeny , Pneumonia, Viral/epidemiology , Protein Biosynthesis , Protein Conformation , RNA, Viral/genetics , Sequence Alignment , Sequence Homology, Nucleic Acid , Viral Proteins/biosynthesis , Viral Proteins/genetics , Viral Proteins/immunology
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