scispace - formally typeset
Search or ask a question
Topic

NSP1

About: NSP1 is a research topic. Over the lifetime, 248 publications have been published within this topic receiving 12044 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: Antiserum prepared against an amino-terminal fragment of rubella virus (RUB) nonstructural polyprotein was used to study RUB-infected Vero cells, indicating that these structures may be the sites of viral RNA synthesis.
Abstract: Antiserum prepared against an amino-terminal fragment of rubella virus (RUB) nonstructural polyprotein was used to study RUB-infected Vero cells. Replicase protein P150 was associated with vesicles and vacuoles of endolysosomal origin and later with large, convoluted, tubular membrane structures. Newly incorporated bromouridine was associated with the same structures and specifically with small membrane invaginations, spherules, indicating that these structures may be the sites of viral RNA synthesis.

70 citations

Journal ArticleDOI
TL;DR: Data show that the RNA-binding domain and the intracellular localization domain lie upstream from the region of NS53 previously determined not to be essential for replication of rotaviruses in cell culture.
Abstract: NS53 (NSP1), the gene 5 product of the group A rotaviruses, is a minor nonstructural protein of 486 to 495 amino acids which binds zinc and contains an amino-terminal highly conserved cysteine-rich region that may form one or two zinc fingers. To study the structure-function of the gene 5 product, wild-type and mutant forms of NS53 were produced by using a recombinant baculovirus expression system and a recombinant vaccinia virus/T7 (vTF7-3) expression system. Analysis of the RNA-binding activity of the wild-type NS53 immobilized onto protein A-Sepharose beads with NS53-specific antiserum showed that the protein exhibited specific affinity for all 11 rotavirus mRNAs. The use of short virus-specific RNA probes indicated that NS53 specifically recognizes an element located near the 5' ends of viral mRNAs. Analysis of the RNA-binding activity of deletion mutants of NS53 showed that the RNA-binding domain resides within the first 81 amino acids of the protein and that the highly conserved cysteine-rich region within this region of the protein is essential for the activity. Gel electrophoresis and Western immunoblot analyses of intracellular fractions derived from infected cells revealed that large amounts of NS53 were present in the cytosol and in association with the cytoskeletal matrix. Indirect immunofluorescence analysis of cells programmed to transiently express mutant forms of NS53 using vTF7-3 indicated that the intracellular localization domain resides between amino acids 84 and 176 of NS53. Together, these data show that the RNA-binding domain and the intracellular localization domain lie upstream from the region of NS53 previously determined not to be essential for replication of rotaviruses in cell culture (J. Hua and J. T. Patton, Virology 198:567-576, 1994).

69 citations

Journal ArticleDOI
TL;DR: This first report on protein-mediated, mRNA-specific control of nidovirus RNA synthesis reveals the existence of an integral control mechanism to fine-tune replication, sg mRNA synthesis, and virus production, and establishes a major role for nsp1 in coordinating the arterivirus replicative cycle.
Abstract: The gene expression of plus-strand RNA viruses with a polycistronic genome depends on translation and replication of the genomic mRNA, as well as synthesis of subgenomic (sg) mRNAs. Arteriviruses and coronaviruses, distantly related members of the nidovirus order, employ a unique mechanism of discontinuous minus-strand RNA synthesis to generate subgenome-length templates for the synthesis of a nested set of sg mRNAs. Non-structural protein 1 (nsp1) of the arterivirus equine arteritis virus (EAV), a multifunctional regulator of viral RNA synthesis and virion biogenesis, was previously implicated in controlling the balance between genome replication and sg mRNA synthesis. Here, we employed reverse and forward genetics to gain insight into the multiple regulatory roles of nsp1. Our analysis revealed that the relative abundance of viral mRNAs is tightly controlled by an intricate network of interactions involving all nsp1 subdomains. Distinct nsp1 mutations affected the quantitative balance among viral mRNA species, and our data implicate nsp1 in controlling the accumulation of full-length and subgenome-length minus-strand templates for viral mRNA synthesis. The moderate differential changes in viral mRNA abundance of nsp1 mutants resulted in similarly altered viral protein levels, but progeny virus yields were greatly reduced. Pseudorevertant analysis provided compelling genetic evidence that balanced EAV mRNA accumulation is critical for efficient virus production. This first report on protein-mediated, mRNA-specific control of nidovirus RNA synthesis reveals the existence of an integral control mechanism to fine-tune replication, sg mRNA synthesis, and virus production, and establishes a major role for nsp1 in coordinating the arterivirus replicative cycle.

68 citations

Journal ArticleDOI
01 Feb 1994-Virology
TL;DR: Results demonstrate that the carboxyl-terminal 233 aa of NS53 are not required for rotavirus replication in vitro, and provide evidence that the subcellular localization signal in NS53 resides in the amino terminal half of the protein.

65 citations

Journal ArticleDOI
TL;DR: Modelling analysis of a newly identified deletion of 3 amino acids of SARS-CoV-2 nsp1 suggests that this deletion could affect the structure of the C-terminal region of the protein, important for regulation of viral replication and negative effect on host’s gene expression.
Abstract: The new Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which was first detected in Wuhan (China) in December of 2019 is responsible for the current global pandemic. Phylogenetic analysis revealed that it is similar to other betacoronaviruses, such as SARS-CoV and Middle-Eastern Respiratory Syndrome, MERS-CoV. Its genome is ∼ 30 kb in length and contains two large overlapping polyproteins, ORF1a and ORF1ab that encode for several structural and non-structural proteins. The non-structural protein 1 (nsp1) is arguably the most important pathogenic determinant, and previous studies on SARS-CoV indicate that it is both involved in viral replication and hampering the innate immune system response. Detailed experiments of site-specific mutagenesis and in vitro reconstitution studies determined that the mechanisms of action are mediated by (a) the presence of specific amino acid residues of nsp1 and (b) the interaction between the protein and the host’s small ribosomal unit. In fact, substitution of certain amino acids resulted in reduction of its negative effects. A total of 17,928 genome sequences were obtained from the GISAID database (December 2019 to July 2020) from patients infected by SARS-CoV-2 from different areas around the world. Genomes alignment was performed using MAFFT (REFF) and the nsp1 genomic regions were identified using BioEdit and verified using BLAST. Nsp1 protein of SARS-CoV-2 with and without deletion have been subsequently modelled using I-TASSER. We identified SARS-CoV-2 genome sequences, from several Countries, carrying a previously unknown deletion of 9 nucleotides in position 686-694, corresponding to the AA position 241-243 (KSF). This deletion was found in different geographical areas. Structural prediction modelling suggests an effect on the C-terminal tail structure. Modelling analysis of a newly identified deletion of 3 amino acids (KSF) of SARS-CoV-2 nsp1 suggests that this deletion could affect the structure of the C-terminal region of the protein, important for regulation of viral replication and negative effect on host’s gene expression. In addition, substitution of the two amino acids (KS) from nsp1 of SARS-CoV was previously reported to revert loss of interferon-alpha expression. The deletion that we describe indicates that SARS-CoV-2 is undergoing profound genomic changes. It is important to: (i) confirm the spreading of this particular viral strain, and potentially of strains with other deletions in the nsp1 protein, both in the population of asymptomatic and pauci-symptomatic subjects, and (ii) correlate these changes in nsp1 with potential decreased viral pathogenicity.

63 citations


Network Information
Related Topics (5)
Viral replication
33.4K papers, 1.6M citations
87% related
Virus
136.9K papers, 5.2M citations
83% related
RNA
111.6K papers, 5.4M citations
79% related
Virulence
35.9K papers, 1.3M citations
79% related
Nucleic acid sequence
41.6K papers, 1.9M citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202126
202020
201910
201810
201711
20169