| NSP2 (rotavirus) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 | |||||||||
| Identifiers | |||||||||
| Symbol | Rota_NS35 | ||||||||
| Pfam | PF02509 | ||||||||
| InterPro | IPR003668 | ||||||||
| CATH | 2gu0 | ||||||||
| SCOP2 | 2r7j / SCOPe / SUPFAM | ||||||||
| |||||||||
| Protein folds into two domains. | |||||||||
NSP2 (NS35), is a rotavirus nonstructural RNA-binding protein that accumulates in cytoplasmic inclusions (viroplasms) and is required for genome replication. [1] NSP2 is closely associated in vivo with the viral replicase. [2] The non-structural protein NSP5 plays a role in the structure of viroplasms mediated by its interaction with NSP2. [3]
Rotavirus is a genus of double-stranded RNA viruses in the family Reoviridae. Rotaviruses are the most common cause of diarrhoeal disease among infants and young children. Nearly every child in the world is infected with a rotavirus at least once by the age of five. Immunity develops with each infection, so subsequent infections are less severe. Adults are rarely affected. There are nine species of the genus, referred to as A, B, C, D, F, G, H, I and J. Rotavirus A, the most common species, causes more than 90% of rotavirus infections in humans.
Severe acute respiratory syndrome–related coronavirus is a species of virus consisting of many known strains phylogenetically related to severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) that have been shown to possess the capability to infect humans, bats, and certain other mammals. These enveloped, positive-sense single-stranded RNA viruses enter host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. The SARSr-CoV species is a member of the genus Betacoronavirus and of the subgenus Sarbecovirus.
Rubella virus (RuV) is the pathogenic agent of the disease rubella, transmitted only between humans via the respiratory route, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
An enterotoxin is a protein exotoxin released by a microorganism that targets the intestines.
The Semliki Forest virus is an alphavirus found in central, eastern, and southern Africa. It was first isolated from mosquitoes in the Semliki Forest, Uganda by the Uganda Virus Research Institute in 1942 and described by Smithburn and Haddow. It is known to cause disease in animals including humans.
Alphavirus is a genus of RNA viruses, the sole genus in the Togaviridae family. Alphaviruses belong to group IV of the Baltimore classification of viruses, with a positive-sense, single-stranded RNA genome. There are 32 alphaviruses, which infect various vertebrates such as humans, rodents, fish, birds, and larger mammals such as horses, as well as invertebrates. Alphaviruses that could infect both vertebrates and arthropods are referred dual-host alphaviruses, while insect-specific alphaviruses such as Eilat virus and Yada yada virus are restricted to their competent arthropod vector. Transmission between species and individuals occurs mainly via mosquitoes, making the alphaviruses a member of the collection of arboviruses – or arthropod-borne viruses. Alphavirus particles are enveloped, have a 70 nm diameter, tend to be spherical, and have a 40 nm isometric nucleocapsid.
Pestivirus is a genus of viruses, in the family Flaviviridae. Viruses in the genus Pestivirus infect mammals, including members of the family Bovidae and the family Suidae. There are 11 species in this genus. Diseases associated with this genus include: hemorrhagic syndromes, abortion, and fatal mucosal disease.
A viroplasm, sometimes called "virus factory" or "virus inclusion", is an inclusion body in a cell where viral replication and assembly occurs. They may be thought of as viral factories in the cell. There are many viroplasms in one infected cell, where they appear dense to electron microscopy. Very little is understood about the mechanism of viroplasm formation.
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template.
Poly(A)-binding protein is an RNA-binding protein which triggers the binding of eukaryotic initiation factor 4 complex (eIF4G) directly to the poly(A) tail of mRNA which is 200-250 nucleotides long. The poly(A) tail is located on the 3' end of mRNA and was discovered by Mary Edmonds, who also characterized the poly-A polymerase enzyme that generates the poly(a) tail. The binding protein is also involved in mRNA precursors by helping polyadenylate polymerase add the poly(A) nucleotide tail to the pre-mRNA before translation. The nuclear isoform selectively binds to around 50 nucleotides and stimulates the activity of polyadenylate polymerase by increasing its affinity towards RNA. Poly(A)-binding protein is also present during stages of mRNA metabolism including nonsense-mediated decay and nucleocytoplasmic trafficking. The poly(A)-binding protein may also protect the tail from degradation and regulate mRNA production. Without these two proteins in-tandem, then the poly(A) tail would not be added and the RNA would degrade quickly.
Rotavirus translation, the process of translating mRNA into proteins, occurs in a different way in Rotaviruses. Unlike the vast majority of cellular proteins in other organisms, in Rotaviruses the proteins are translated from capped but nonpolyadenylated mRNAs. The viral nonstructural protein NSP3 specifically binds the 3'-end consensus sequence of viral mRNAs and interacts with the eukaryotic translation initiation factor eIF4G. The Rotavirus replication cycle occurs entirely in the cytoplasm. Upon virus entry, the viral transcriptase synthesizes capped but nonpolyadenylated mRNA The viral mRNAs bear 5' and 3' untranslated regions (UTR) of variable length and are flanked by two different sequences common to all genes.
RoXaN also known as ZC3H7B, is a protein that in humans is encoded by the ZC3H7B gene. RoXaN is a protein that contains tetratricopeptide repeat and leucine-aspartate repeat as well as zinc finger domains. This protein also interacts with the rotavirus non-structural protein NSP3.
In virology, a nonstructural protein is a protein encoded by a virus but that is not part of the viral particle. They typically include the various enzymes and transcription factors the virus uses to replicate itself, such as a viral protease, an RNA replicase or other template-directed polymerases, and some means to control the host.
NSP1 (NS53), the product of rotavirus gene 5, is a nonstructural RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates. RNA-folding predictions suggest that this region of the NSP1 mRNA can interact with itself, producing a stem-loop structure similar to that found near the 5'-terminus of the NSP1 mRNA.
Rotavirus protein NSP3 (NS34) is bound to the 3' end consensus sequence of viral mRNAs in infected cells.
The rotavirus nonstructural protein NSP4 was the first viral enterotoxin discovered. It is a viroporin and induces diarrhea and causes Ca2+-dependent transepithelial secretion.
NSP5 encoded by genome segment 11 of group A rotaviruses. In virus-infected cells NSP5 accumulates in the viroplasms. NSP5 has been shown to be autophosphorylated. Interaction of NSP5 with NSP2 was also demonstrated. In rotavirus-infected cells, the non-structural proteins NSP5 and NSP2 localize in complexes called viroplasms, where replication and assembly occur and they can drive the formation of viroplasm-like structures in the absence of other rotaviral proteins and rotavirus replication.
Putative transmembrane domain more commonly known as Non-structural Protein 6 (NSP6) is one of the two non-structural proteins that gene 11 in rotavirus encodes for alongside NSP5. NSP6 is composed of six transmembrane domains and a C terminal tail. In contrast to the other rotavirus non-structural proteins, NSP6 was found to have a high rate of turnover, being completely degraded within 2 hours of synthesis. NSP6 was found to be a sequence-independent nucleic acid binding protein, with similar affinities for ssRNA and dsRNA
Rev is a transactivating protein that is essential to the regulation of HIV-1 protein expression. A nuclear localization signal is encoded in the rev gene, which allows the Rev protein to be localized to the nucleus, where it is involved in the export of unspliced and incompletely spliced mRNAs. In the absence of Rev, mRNAs of the HIV-1 late (structural) genes are retained in the nucleus, preventing their translation.
ORF1ab refers collectively to two open reading frames (ORFs), ORF1a and ORF1b, that are conserved in the genomes of nidoviruses, a group of viruses that includes coronaviruses. The genes express large polyproteins that undergo proteolysis to form several nonstructural proteins with various functions in the viral life cycle, including proteases and the components of the replicase-transcriptase complex (RTC). Together the two ORFs are sometimes referred to as the replicase gene. They are related by a programmed ribosomal frameshift that allows the ribosome to continue translating past the stop codon at the end of ORF1a, in a -1 reading frame. The resulting polyproteins are known as pp1a and pp1ab.
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