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ORF3a
ORF3a (previously known as X1 or U274) is a gene found in coronaviruses of the subgenus ''Sarbecovirus'', including SARS-CoV and SARS-CoV-2. It encodes an accessory protein about 275 amino acid residues long, which is thought to function as a viroporin. It is the largest accessory protein and was the first of the SARS-CoV accessory proteins to be described. Comparative genomics ORF3a is well conserved within the subgenus ''Sarbecovirus''. The protein has 73% sequence identity between SARS-CoV (274 residues) and SARS-CoV-2 (275 residues). Within the ORF3a open reading frame there are several overlapping genes in the genome: ORF3a, ORF3b, and (in SARS-CoV-2 only) ORF3c. In SARS-CoV-2, the overlap between ORF3a, ORF3c, and ORF3d potentially represents a rare example of all three possible reading frames of the same sequence region encoding functional proteins. Although ORF3a is present in ''Sarbecovirus'', it is absent in another ''Betacoronavirus'' subgenus, ''Embecovirus'', whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ORF3c
ORF3c is a gene found in coronaviruses of the subgenus ''Sarbecovirus'', including SARS-CoV and SARS-CoV-2. It was first identified in the SARS-CoV-2 genome and encodes a 41 amino acid non-structural protein of unknown function. It is also present in the SARS-CoV genome, but was not recognized until the identification of the SARS-CoV-2 homolog. Nomenclature There has been significant confusion in the scientific literature around the nomenclature used for the accessory proteins of SARS-CoV-2, especially several overlapping genes with ORF3a. The predicted protein product of the ''ORF3c'' gene has at least once been referred to as "3b protein", but it is not to be confused with the non-homologous gene '' ORF3b''. It has also been described under the names ''ORF3h'' and ''ORF3a.iORF1''. The recommended nomenclature for SARS-CoV-2 uses the term ''ORF3c'' for this gene. Comparative genomics ORF3c is an overlapping gene whose open reading frame overlaps both ORF3a and ORF3d in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ORF3b
ORF3b is a gene found in coronaviruses of the subgenus ''Sarbecovirus'', encoding a short non-structural protein. It is present in both SARS-CoV (which causes the disease SARS) and SARS-CoV-2 (which causes COVID-19), though the protein product has very different lengths in the two viruses. The encoded protein is significantly shorter in SARS-CoV-2, at only 22 amino acid residues compared to 153-155 in SARS-CoV. Both the longer SARS-CoV and shorter SARS-CoV-2 proteins have been reported as interferon antagonists. It is unclear whether the SARS-CoV-2 gene expresses a functional protein. Nomenclature There has been significant confusion in the scientific literature around the nomenclature used for the accessory proteins of SARS-CoV-2, especially several overlapping genes with ORF3a. Due to differences in the genomes of SARS-CoV and SARS-CoV-2, two distinct open reading frames (ORFs) in the SARS-CoV-2 genome have been referred to as "ORF3b". In SARS-CoV, ORF3b is a gene of 155 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarbecovirus
''Severe acute respiratory syndrome–related coronavirus'' (SARSr-CoV or SARS-CoV)The terms ''SARSr-CoV'' and ''SARS-CoV'' are sometimes used interchangeably, especially prior to the discovery of SARS-CoV-2. This may cause confusion when some publications refer to SARS-CoV-1 as ''SARS-CoV''. 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'' (SARS Betacoronavirus). Two strains of the virus have caused outbreaks of severe respiratory diseases in humans: severe acute respiratory syndrome coronavirus 1 (SARS-CoV or SARS-CoV-1), which caused th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryo-electron Microscopy
Cryogenic electron microscopy (cryo-EM) is a cryomicroscopy technique applied on samples cooled to cryogenic temperatures. For biological specimens, the structure is preserved by embedding in an environment of vitreous ice. An aqueous sample solution is applied to a grid-mesh and plunge-frozen in liquid ethane or a mixture of liquid ethane and propane. While development of the technique began in the 1970s, recent advances in detector technology and software algorithms have allowed for the determination of biomolecular structures at near-atomic resolution. This has attracted wide attention to the approach as an alternative to X-ray crystallography or NMR spectroscopy for macromolecular structure determination without the need for crystallization. In 2017, the Nobel Prize in Chemistry was awarded to Jacques Dubochet, Joachim Frank, and Richard Henderson "for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution." ''Nature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching prim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Coronavirus OC43
Human coronavirus OC43 (HCoV-OC43) is a member of the species '' Betacoronavirus 1'', which infects humans and cattle. The infecting coronavirus is an enveloped, positive-sense, single-stranded RNA virus that enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid receptor. OC43 is one of seven coronaviruses known to infect humans. It is one of the viruses responsible for the common cold and may have been responsible for the 1889–1890 pandemic. It has, like other coronaviruses from genus '' Betacoronavirus,'' subgenus '' Embecovirus'', an additional shorter spike protein called hemagglutinin-esterase (HE). Virology Four HCoV-OC43 genotypes (A to D) have been identified, with genotype D most likely arising from genetic recombination. The complete genome sequencing of genotypes C and D and bootscan analysis shows recombination events between genotypes B and C in the generation of genotype D. Of 29 viral variants identified, none belong to the more ancient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merbecovirus
''Merbecovirus'' is a subgenus of viruses in the genus ''Betacoronavirus'', including the human pathogen Middle East respiratory syndrome–related coronavirus (MERS-CoV). The viruses in this subgenus were previously known as group 2c coronaviruses. Structure The viruses of this subgenus, like other coronaviruses, have a lipid bilayer envelope in which the membrane (M), envelope (E) and spike (S) structural proteins are anchored. See also *''Embecovirus'' (group 2a) *''Sarbecovirus'' (group 2b) *''Nobecovirus ''Nobecovirus'' is a subgenus of viruses in the genus ''Betacoronavirus''. The viruses in the group were previously known as group 2d coronaviruses. Structure The viruses of this subgenus, like other coronaviruses, have a lipid bilayer envelope ...'' (group 2d) References Virus subgenera Betacoronaviruses {{Virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MERS-CoV
''Middle East respiratory syndrome–related coronavirus'' (''MERS-CoV''), or EMC/2012 ( HCoV-EMC/2012), is the virus that causes Middle East respiratory syndrome (MERS). It is a species of coronavirus which infects humans, bats, and camels. The infecting virus is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the DPP4 receptor. The species is a member of the genus '' Betacoronavirus'' and subgenus ''Merbecovirus''. Initially called simply novel coronavirus or nCoV, it was first reported in June 2012 after genome sequencing of a virus isolated from sputum samples from a person who fell ill in a 2012 outbreak of a new flu-like respiratory illness. By July 2015, MERS-CoV cases had been reported in over 21 countries, in Europe, North America and Asia as well as the Middle East. MERS-CoV is one of several viruses identified by the World Health Organization (WHO) as a likely cause of a future epidemic. They list it for urgent rese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Coronavirus 229E
''Human coronavirus 229E'' (''HCoV-229E'') is a species of coronavirus which infects humans and bats. It is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the APN receptor. Along with Human coronavirus OC43 (a member of the '' Betacoronavirus'' genus), it is one of the viruses responsible for the common cold. HCoV-229E is a member of the genus '' Alphacoronavirus'' and subgenus ''Duvinacovirus''. Transmission HCoV-229E transmits via droplet-respiration and fomites. Signs and symptoms HCoV-229E is associated with a range of respiratory symptoms, ranging from the common cold to high-morbidity outcomes such as pneumonia and bronchiolitis. However, such high morbidity outcomes are almost always seen in cases with co-infection with other respiratory pathogens; there is a single published case report to date of a 229E infection that caused acute respiratory distress syndrome (ARDS) in an otherwise healthy patient having no detec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphacoronavirus
Alphacoronaviruses (Alpha-CoV) are members of the first of the four genera (''Alpha''-, '' Beta-'', '' Gamma-'', and '' Delta-'') of coronaviruses. They are positive-sense, single-stranded RNA viruses that infect mammals, including humans. They have spherical virions with club-shaped surface projections formed by trimers of the spike protein, and a viral envelope. Alphacoronaviruses are in the subfamily ''Orthocoronavirinae'' of the family '' Coronaviridae''. Both the ''Alpha''- and ''Betacoronavirus'' lineages descend from the bat viral gene pool. Alphacoronaviruses were previously known as "phylogroup 1 coronaviruses". The Alphacoronavirus genus is very diverse, particularly in bats. Most bat originating strains haven't been successfully isolated and cultured in laboratory. Alphacoronaviruses infecting other mammal species have been much better studied, see List of Coronavirus live isolates. Etymology The name alphacoronavirus is derived from Ancient Greek ἄλφα ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embecovirus
''Embecovirus'' is a subgenus of coronaviruses in the genus ''Betacoronavirus''. The viruses in this subgenus, unlike other coronaviruses, have a hemagglutinin esterase (HE) gene. The viruses in the subgenus were previously known as group 2a coronaviruses. Structure The viruses of this subgenus, like other coronaviruses, have a lipid bilayer envelope in which the membrane (M), envelope (E) and spike (S) structural proteins are anchored. Unlike other coronaviruses, viruses in this subgenus also have an additional shorter spike-like structural protein called hemagglutinin esterase (HE). Recombination Genetic recombination can occur when two or more viral genomes are present in the same host cell. The dromedary camel beta-coronavirus (Beta-CoV HKU23) exhibits genetic diversity in the African camel population.Diversity of Dromedary Camel Coronavirus HKU23 in African Camels Revealed Multiple Recombination Events among Closely Related Betacoronaviruses of the Subgenus Embecoviru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Coronavirus NL63
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically modern hum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
