Orthoreovirus
Orthoreovirus, Mammalian
Orthoreovirus, Avian
Boidae
Reoviridae
Mammalian orthoreovirus 3
Molecular Sequence Data
Sequence Homology, Amino Acid
Encyclopedias as Topic
Tenosynovitis
Sequential partially overlapping gene arrangement in the tricistronic S1 genome segments of avian reovirus and Nelson Bay reovirus: implications for translation initiation. (1/58)
Previous studies of the avian reovirus strain S1133 (ARV-S1133) S1 genome segment revealed that the open reading frame (ORF) encoding the final sigmaC viral cell attachment protein initiates over 600 nucleotides distal from the 5' end of the S1 mRNA and is preceded by two predicted small nonoverlapping ORFs. To more clearly define the translational properties of this unusual polycistronic RNA, we pursued a comparative analysis of the S1 genome segment of the related Nelson Bay reovirus (NBV). Sequence analysis indicated that the 3'-proximal ORF present on the NBV S1 genome segment also encodes a final sigmaC homolog, as evidenced by the presence of an extended N-terminal heptad repeat characteristic of the coiled-coil region common to the cell attachment proteins of reoviruses. Most importantly, the NBV S1 genome segment contains two conserved ORFs upstream of the final sigmaC coding region that are extended relative to the predicted ORFs of ARV-S1133 and are arranged in a sequential, partially overlapping fashion. Sequence analysis of the S1 genome segments of two additional strains of ARV indicated a similar overlapping tricistronic gene arrangement as predicted for the NBV S1 genome segment. Expression analysis of the ARV S1 genome segment indicated that all three ORFs are functional in vitro and in virus-infected cells. In addition to the previously described p10 and final sigmaC gene products, the S1 genome segment encodes from the central ORF a 17-kDa basic protein (p17) of no known function. Optimizing the translation start site of the ARV p10 ORF lead to an approximately 15-fold increase in p10 expression with little or no effect on translation of the downstream final sigmaC ORF. These results suggest that translation initiation complexes can bypass over 600 nucleotides and two functional overlapping upstream ORFs in order to access the distal final sigmaC start site. (+info)Subunit composition and conformational stability of the oligomeric form of the avian reovirus cell-attachment protein sigmaC. (2/58)
Previous work has shown that the avian reovirus cell-attachment sigma C (sigmaC) protein is a multimer. In the first part of this study the oligomerization state of intracellularly synthesized sigmaC was analysed by different approaches, including SDS-PAGE, chemical cross-linking, sedimentation and gel filtration analysis. All these approaches indicated that protein sigmaC in its native state is a homotrimer. In the second part of the present work we investigated the effect of different factors and reagents on oligomer stability, in order to elucidate the nature of the forces that maintain the conformational stability of the homotrimer. Our results, based on the stabilizing effect conferred by reducing agents, demonstrate that the sigmaC subunits are not covalently bound via disulfide linkages. They further suggest that the formation of an intrachain disulfide bond between the two cysteine residues of the sigmaC polypeptide has a negative effect on oligomer stability. The susceptibility of the trimer to pH, temperature, ionic strength, chemical denaturants and detergents indicates that hydrophobic interactions contribute much more to oligomer stability than do ionic interactions and hydrogen bonding. Finally, our results also reveal that mammalian and avian reovirus cell attachment proteins follow different subunit dissociation pathways. (+info)The avian reovirus genome segment S1 is a functionally tricistronic gene that expresses one structural and two nonstructural proteins in infected cells. (3/58)
The avian reovirus S1 gene contains three partially overlapping, out-of-phase open reading frames (ORFs) that the highly conserved in all avian reovirus strains examined to date. The three S1 ORFs of the avian reovirus strain S1133 were individually expressed in bacterial cells, and their purified translation products used as antigens to raise specific polyclonal antibodies. With these antibodies we were able to demonstrate that all three S1 ORFs from different avian reovirus strains are translatable in infected cells. Proteins p10 and p17, which are specified by ORF1 and ORF2, respectively, are nonstructural proteins which associate with cell membranes, whereas ORF3 directs the synthesis of protein sigma C, a structural oligomeric protein responsible for cell attachment. While intracellular synthesis of protein sigma C was demonstrated a long time ago and that of protein p10 was reported recently, this is the first time that expression of the S1 ORF2 has been demonstrated experimentally. Thus, the previously reported coding capacity of the avian reovirus genome is now expanded to 14 proteins, of which ten are structural (lambda A, lambda B, lambda C, microA, microB, microBC, microBN, sigma A, sigma B, and sigma C) and four are nonstructural (microNS, sigma NS, p17, and p10). Finally, protein p10, but not p17 or sigma C, induces cell-cell fusion when transiently expressed in mammalian cells, supporting a previously published observation that the polypeptide encoded by the S1 ORF1 plays an important role in the syncytial phenotype displayed by avian reoviruses. (+info)Evidence of nucleotidyl phosphatase activity associated with core protein sigma A of avian reovirus S1133. (4/58)
Both avian reovirus core protein sigma A purified from virus-infected cell extracts and the purified bacterially expressed protein sigma A (e sigma A) were characterized for their nucleoside triphosphate (NTP) hydrolysis activity by thin-layer chromotography. Protein sigma A from both preparations has a nonspecific nucleotidyl phosphatase activity that hydrolyzes four types of NTP to their corresponding nucleoside di- and monophosphates and free phosphate. The divalent cation requirement for this activity of e sigma A was further examined by the addition of Mn(2+), Mg(2+), Ca(2+), and Zn(2+) ions. NTP hydrolysis by e sigma A was maximal when Mn(2+), Mg(2+), or Ca(2+) concentrations were 5, 4, or 1 mM, respectively. Addition of Mn(2+) or Mg(2+) stimulated the reactions up to 4- or 3-fold, respectively, higher than Ca(2+) (2.2-fold). However, Zn(2+) ion inhibited this activity of e sigma A. The results suggest that nucleotidyl phosphatase activity of e sigma A is absolutely dependent on the divalent cations Mn(2+), Mg(2+), or Ca(2+), but not Zn(2+). Similar results were obtained from the analysis of divalent cation requirements for the protein sigma A nucleotidyl phosphatase activity. Optimal pH for nucleotidyl phosphatase activity of protein sigma A from both preparations was determined using reaction mixtures buffered at different pH. The results show that the optimal activities of both proteins were similar and were achieved between pH 7.5 and 8.5. (+info)Modification of late membrane permeability in avian reovirus-infected cells: viroporin activity of the S1-encoded nonstructural p10 protein. (5/58)
Infection of chicken embryo fibroblasts by avian reovirus induces an increase in the permeability of the host plasma membrane at late, but not early, infection times. The absence of permeability changes at early infection times, as well as the dependence of late membrane modification on both viral protein synthesis and an active exocytic route, suggest that a virus-encoded membrane protein is required for avian reovirus to permeabilize cells. Further studies revealed that expression of nonstructural p10 protein in bacterial cells arrested cell growth and enhanced membrane permeability. Membrane leakiness was also observed following transient expression of p10 in BSC-40 monkey cells. Both its permeabilizing effect and the fact that p10 shares several structural and physical characteristics with other membrane-active viral proteins indicate that p10 is an avian reovirus viroporin. Furthermore, the fusogenic extracellular NH(2)-terminal domain of p10 appears to be dispensable for permeabilizing activity, because its deletion entirely abolished the fusogenic activity of p10, without affecting its ability to associate with cell membranes and to enhance membrane permeability. Similar properties have reported previously for immunodeficiency virus type I transmembrane glycoprotein gp41. Thus, like gp41, p10 appears to be a multifunctional protein that plays key roles in virus-host interaction. (+info)Muscovy duck reovirus sigmaC protein is atypically encoded by the smallest genome segment. (6/58)
Although muscovy duck reovirus (DRV) shares properties with the reovirus isolated from chicken, commonly named avian reovirus (ARV), the two virus species are antigenically different. Similar to the DRV sigmaB-encoded gene (1201 bp long) previously identified, the three other double-stranded RNA small genome segments of DRV have been cloned and sequenced. They were 1325, 1191 and 1124 bp long, respectively, and contained conserved terminal sequences common to ARVs. They coded for single expression products, except the smallest (S4), which contained two overlapping open reading frames (ORF1 and ORF2). BLAST analyses revealed that the proteins encoded by the 1325 and 1191 bp genes shared high identity levels with ARV sigmaA and sigmaNS, respectively, and to a lesser extent with other orthoreovirus counterparts. No homology was found for the S4 ORF1-encoded p10 protein. The 29.4 kDa product encoded by S4 ORF2 appeared to be 25% identical to ARV S1 ORF3-encoded sigmaC, a cell-attachment oligomer inducing type-specific neutralizing antibodies. Introduction of large gaps in the N-terminal part of the DRV protein was necessary to improve DRV and ARV sigmaC amino acid sequence alignments. However, a leucine zipper motif was conserved and secondary structure analyses predicted a three-stranded alpha-helical coiled-coil feature at this amino portion. Thus, despite extensive sequence divergence, DRV sigmaC was suggested to be structurally and probably functionally related to ARV sigmaC. This work provides evidence for the diversity of the polycistronic S class genes of reoviruses isolated from birds and raises the question of the relative classification of DRV in the Orthoreovirus genus. (+info)Diarrhea-inducing activity of avian rotavirus NSP4 glycoproteins, which differ greatly from mammalian rotavirus NSP4 glycoproteins in deduced amino acid sequence in suckling mice. (7/58)
Avian rotavirus NSP4 glycoproteins expressed in Escherichia coli acted as enterotoxins in suckling mice, as did mammalian rotavirus NSP4 glycoproteins, despite great differences in the amino acid sequences. The enterotoxin domain of PO-13 NSP4 exists in amino acid residues 109 to 135, a region similar to that reported in SA11 NSP4. (+info)Cloning, expression, and characterization of avian reovirus guanylyltransferase. (8/58)
We have cloned and sequenced the L3 genome segment of avian reovirus strain 1733, which specifies the viral guanylyltransferase protein, lambdaC. The L3 gene is 3907 nucleotides long and encodes, in a single large open-reading frame, a polypeptide of 1285 amino acid residues, with a calculated M(r) of 142.2 kDa. Expression of this gene in a baculovirus/insect cell system produced a recombinant protein that comigrated with reovirion lambdaC and reacted with anti-reovirus polyclonal serum in a Western blot assay. Incubation of recombinant lambdaC with GTP led to the formation GMP-lambdaC complex via a phosphoamide linkage. Interestingly, a 42-kDa amino-terminal proteolytic fragment of recombinant lambdaC protein also exhibited autoguanylylation activity, demonstrating both that this fragment is necessary and sufficient for autoguanylylation activity and that the 100-kDa complementary fragment is expendable for that activity. Comparison of the deduced amino acid sequence of protein lambdaC with those of the mammalian and grass carp reovirus guanylyltransferases revealed that only two of eight lysine residues within the amino-terminal 42-kDa region are conserved. Interestingly, these two lysines match with the lysine residues in the mammalian reovirus capping enzyme proposed to be essential for autoguanylylation activity. Our alignment analysis also showed that the S-adenosyl-l-methionine-binding pocket previously detected in the mammalian reovirus capping enzyme is fully conserved in its avian and grass carp reovirus counterparts, suggesting that all three enzymes have methylase activity. (+info)Orthoreovirus is a type of virus that belongs to the family Reoviridae. These are non-enveloped viruses with a double-stranded RNA genome. Orthoreoviruses are further classified into three main serotypes (Orthoreovirus 1-3), and they are known to infect both humans and animals, including birds and mammals.
In humans, orthoreovirus infections are usually mild or asymptomatic but can sometimes cause respiratory or gastrointestinal symptoms, particularly in children. The virus is typically transmitted through respiratory droplets or the fecal-oral route. Once inside the host, the virus infects and replicates within cells of the respiratory or intestinal tract, leading to tissue damage and the release of pro-inflammatory cytokines.
Orthoreovirus infections are generally self-limiting, and treatment is typically supportive. However, there is ongoing research into the potential use of orthoreoviruses as oncolytic viruses for cancer therapy, as they have been shown to selectively infect and kill cancer cells while leaving normal cells unharmed.
Orthoreovirus, mammalian, refers to a genus of viruses in the family Reoviridae that primarily infect mammals. These non-enveloped viruses have a segmented double-stranded RNA genome and an icosahedral symmetry. They are typically associated with asymptomatic or mild respiratory or enteric infections in various mammalian hosts, including humans. However, they can sometimes cause more severe diseases in immunocompromised individuals. The genus includes three species: Mammalian orthoreovirus (MRV), Nelson Bay orthoreovirus (NBORV), and Baboon orthoreovirus (BRV).
Orthoreovirus, avian refers to a type of orthoreovirus that primarily infects birds. Orthoreoviruses are non-enveloped, double-stranded RNA viruses belonging to the family Reoviridae. The avian orthoreoviruses are divided into three groups based on their host range and serological properties: orthoreovirus group 1 (avian reovirus), orthoreovirus group 2 (fiscal reovirus), and orthoreovirus group 3 (ptarmigan reovirus). Avian reoviruses are the most well-known and studied among these, causing various diseases in poultry, such as viral arthritis/tenosynovitis, runting-stunting syndrome, and enteric disease. They have a segmented genome consisting of 10 separate RNA segments that encode for several structural and non-structural proteins involved in virus replication, assembly, and pathogenesis.
Reoviridae infections refer to diseases caused by the Reoviridae family of viruses, which are non-enveloped, double-stranded RNA viruses. These viruses are widespread and can infect a variety of hosts, including humans, animals, and insects. The infection typically causes mild respiratory or gastrointestinal symptoms in humans, such as cough, runny nose, sore throat, and diarrhea. In some cases, Reoviridae infections may also lead to more severe diseases, such as meningitis or encephalitis, particularly in immunocompromised individuals. However, it's worth noting that many Reoviridae infections are asymptomatic and do not cause any noticeable illness.
Reoviridae viruses include several genera, such as Orthoreovirus, Rotavirus, Coltivirus, and Orbivirus, among others. Some of the most well-known human pathogens in this family include Rotaviruses, which are a leading cause of severe diarrheal disease in young children worldwide, and Orthoreoviruses, which can cause respiratory illnesses.
Treatment for Reoviridae infections is generally supportive, focusing on managing symptoms such as fever, dehydration, and pain. Antiviral medications are not typically used to treat these infections. Prevention measures include good hygiene practices, such as handwashing and avoiding close contact with infected individuals, as well as vaccination against specific Reoviridae viruses, such as Rotavirus vaccines.
Boidae is a family of snakes, also known as boas. This family includes many different species of large, non-venomous snakes found in various parts of the world, particularly in Central and South America, Africa, and Asia. Boas are known for their strong bodies and muscular tails, which they use to constrict their prey before swallowing it whole. Some well-known members of this family include the anaconda, the python, and the boa constrictor.
Reoviridae is a family of double-stranded RNA viruses that are non-enveloped and have a segmented genome. The name "Reoviridae" is derived from Respiratory Enteric Orphan virus, as these viruses were initially discovered in respiratory and enteric (gastrointestinal) samples but did not appear to cause any specific diseases.
The family Reoviridae includes several important human pathogens such as rotaviruses, which are a major cause of severe diarrhea in young children worldwide, and orthoreoviruses, which can cause respiratory and systemic infections in humans. Additionally, many Reoviridae viruses infect animals, including birds, mammals, fish, and insects, and can cause a variety of diseases.
Reoviridae virions are typically composed of multiple protein layers that encase the genomic RNA segments. The family is divided into two subfamilies, Sedoreovirinae and Spinareovirinae, based on structural features and genome organization. Reoviruses have a complex replication cycle that involves multiple steps, including attachment to host cells, uncoating of the viral particle, transcription of the genomic RNA, translation of viral proteins, packaging of new virions, and release from infected cells.
A viral genome is the genetic material (DNA or RNA) that is present in a virus. It contains all the genetic information that a virus needs to replicate itself and infect its host. The size and complexity of viral genomes can vary greatly, ranging from a few thousand bases to hundreds of thousands of bases. Some viruses have linear genomes, while others have circular genomes. The genome of a virus also contains the information necessary for the virus to hijack the host cell's machinery and use it to produce new copies of the virus. Understanding the genetic makeup of viruses is important for developing vaccines and antiviral treatments.
Mammalian Orthoreovirus 3 (Reovirus 3) is a species in the Reoviridae family, Orthoreovirus genus. It is a non-enveloped, double-stranded RNA virus with a segmented genome. This virus is known to infect various mammals, including humans, and primarily targets the respiratory and gastrointestinal systems. However, it generally does not cause any noticeable symptoms or diseases in immunocompetent individuals. The virus has been studied for its potential use as an oncolytic agent in cancer therapy due to its ability to selectively infect and kill cancer cells.
Phylogeny is the evolutionary history and relationship among biological entities, such as species or genes, based on their shared characteristics. In other words, it refers to the branching pattern of evolution that shows how various organisms have descended from a common ancestor over time. Phylogenetic analysis involves constructing a tree-like diagram called a phylogenetic tree, which depicts the inferred evolutionary relationships among organisms or genes based on molecular sequence data or other types of characters. This information is crucial for understanding the diversity and distribution of life on Earth, as well as for studying the emergence and spread of diseases.
A viral RNA (ribonucleic acid) is the genetic material found in certain types of viruses, as opposed to viruses that contain DNA (deoxyribonucleic acid). These viruses are known as RNA viruses. The RNA can be single-stranded or double-stranded and can exist as several different forms, such as positive-sense, negative-sense, or ambisense RNA. Upon infecting a host cell, the viral RNA uses the host's cellular machinery to translate the genetic information into proteins, leading to the production of new virus particles and the continuation of the viral life cycle. Examples of human diseases caused by RNA viruses include influenza, COVID-19 (SARS-CoV-2), hepatitis C, and polio.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Tenosynovitis is a medical condition characterized by inflammation of the lining (synovium) surrounding a tendon, which is a cord-like structure that attaches muscle to bone. This inflammation can cause pain, swelling, and difficulty moving the affected joint. Tenosynovitis often affects the hands, wrists, feet, and ankles, and it can result from various causes, including infection, injury, overuse, or autoimmune disorders like rheumatoid arthritis. Prompt diagnosis and treatment of tenosynovitis are essential to prevent complications such as tendon rupture or chronic pain.