Betacoronavirus

Betacoronaviruses (β-CoVs or Beta-CoVs) are one of four genera of coronaviruses of the subfamily Orthocoronavirinae in the family Coronaviridae, of the order Nidovirales. They are enveloped, positive-sense, single-stranded RNA viruses of zoonotic origin. The coronavirus genera are each composed of varying viral lineages with the betacoronavirus genus containing four such lineages. In older literature, this genus is also known as group 2 coronaviruses.

Betacoronavirus
MERS-CoV particles as seen by negative stain electron microscopy. Virions contain characteristic club-like projections emanating from the viral membrane.
MERS-CoV particles as seen by negative stain electron microscopy. Virions contain characteristic club-like projections emanating from the viral membrane.
SARS-CoV-2 without background.png
Illustration of a SARS-CoV-2 virion
Virus classification e
(unranked): Virus
Realm: Riboviria
Phylum: incertae sedis
Order: Nidovirales
Family: Coronaviridae
Subfamily: Orthocoronavirinae
Genus: Betacoronavirus
Subgenera and Species[1][2]

The Beta-CoVs of the greatest clinical importance concerning humans are OC43 and HKU1 of the A lineage, SARS-CoV and SARS-CoV-2 (which causes the disease COVID-19) of the B lineage,[3] and MERS-CoV of the C lineage. MERS-CoV is the first betacoronavirus belonging to lineage C that is known to infect humans.[4][5]

The Alphacoronavirus and Betacoronavirus genera descend from the bat gene pool.[6][7][8]

VirologyEdit

Alpha- and Betacoronaviruses mainly infect bats, but they also infect other species like humans, camels, and rabbits.[6][7][8][9] Beta-CoVs that have caused epidemics in humans generally induce fever and respiratory symptoms. They include:

SequenceEdit

Coronaviruses have a large genome size that ranges from 26 to 32 kilobases. The overall structure of β-CoV genome is similar to that of other CoVs, with an ORF1ab replicase polyprotein (rep, pp1ab) preceding other elements. This polyprotein is cleaved into many nonstructural proteins (see UniProt annotation of SARS rep, P0C6X7).

As of May 2013, GenBank has 46 published complete genomes of the α- (group 1), β- (group 2), γ- (group 3), and δ- (group 4) CoVs.[10]

ClassificationEdit

 
Diagram of coronavirus virion structure showing spikes that form "crown" like the solar corona, hence the name.
 
Illustration of SARSr-CoV virion

Within the genus Betacoronavirus (Group 2 CoV), four lineages (a, b, c, and d) are commonly recognized.[11]

  • Lineage A (subgenus Embecovirus) includes HCoV-OC43 and HCoV-HKU1 (various species)
  • Lineage B (subgenus Sarbecovirus) includes SARSr-CoV (which includes all its strains such as SARS-CoV, SARS-CoV-2, and Bat SL-CoV-WIV1)
  • Lineage C (subgenus Merbecovirus) includes Tylonycteris bat coronavirus HKU4 (BtCoV-HKU4), Pipistrellus bat coronavirus HKU5 (BtCoV-HKU5), and MERS-CoV (various species)
  • Lineage D (subgenus Nobecovirus) includes Rousettus bat coronavirus HKU9 (BtCoV-HKU9)[12]

The four lineages have also been named using Greek letters or numerically.[10] A further subgenus is Hibecovirus including Bat Hp-betacoronavirus Zhejiang2013.[1][13]

MorphologyEdit

The viruses of lineage A differ from all others in the genus in that they have a shorter spike-like protein called hemagglutinin esterase (HE).[11]

The name Coronavirus is derived from Latin corona, meaning 'crown' or 'halo', referring to their image under electron microscopy of crown-like spikes on their surface similar to the solar corona. This morphology is created by the viral spike (S) peplomers, which are proteins that populate the surface of the virus and determine host tropism. The order Nidovirales is named for the Latin nidus, which means 'nest'. It refers to this order's production of a 3′-coterminal nested set of subgenomic mRNAs during infection.[14]

Several structures of the spike proteins have been resolved. The receptor binding domain in Alpha- and Betacoronavirus spike protein is catalogued as InterProIPR018548.[15] The spike protein assembles into a trimer (PDB: 3jcl, 6acg​); its core structure resembles that of paramyxovirus F (fusion) proteins.[16] The receptor usage is not very conserved; for example, among Sarbecovirus, only a sub-lineage containing SARS share the ACE2 receptor.[17]

See alsoEdit

ReferencesEdit

  1. ^ a b "Virus Taxonomy: 2018 Release". International Committee on Taxonomy of Viruses (ICTV). October 2018. Retrieved 13 January 2019.
  2. ^ Woo, Patrick C. Y.; Huang, Yi; Lau, Susanna K. P.; Yuen, Kwok-Yung (2010-08-24). "Coronavirus Genomics and Bioinformatics Analysis". Viruses. 2 (8): 1804–1820. doi:10.3390/v2081803. ISSN 1999-4915. PMC 3185738. PMID 21994708. Figure 2. Phylogenetic analysis of RNA-dependent RNA polymerases (Pol) kharghar is the best of coronaviruses with complete genome sequences available. The tree was constructed by the neighbor-joining method and rooted using Breda virus polyprotein.
  3. ^ "Phylogeny of SARS-like betacoronaviruses". nextstrain. Retrieved 18 January 2020.
  4. ^ ProMED. MERS-CoV–Eastern Mediterranean (06) (http://www.promedmail.org/)
  5. ^ Memish, Z. A.; Zumla, A. I.; Al-Hakeem, R. F.; Al-Rabeeah, A. A.; Stephens, G. M. (2013). "Family Cluster of Middle East Respiratory Syndrome Coronavirus Infections". New England Journal of Medicine. 368 (26): 2487–94. doi:10.1056/NEJMoa1303729. PMID 23718156.
  6. ^ a b Woo, P. C.; Wang, M.; Lau, S. K.; Xu, H.; Poon, R. W.; Guo, R.; Wong, B. H.; Gao, K.; Tsoi, H. W.; Huang, Y.; Li, K. S.; Lam, C. S.; Chan, K. H.; Zheng, B. J.; Yuen, K. Y. (2007). "Comparative analysis of twelve genomes of three novel group 2c and group 2d coronaviruses reveals unique group and subgroup features". Journal of Virology. 81 (4): 1574–85. doi:10.1128/JVI.02182-06. PMC 1797546. PMID 17121802.
  7. ^ a b Lau, S. K.; Woo, P. C.; Yip, C. C.; Fan, R. Y.; Huang, Y.; Wang, M.; Guo, R.; Lam, C. S.; Tsang, A. K.; Lai, K. K.; Chan, K. H.; Che, X. Y.; Zheng, B. J.; Yuen, K. Y. (2012). "Isolation and characterization of a novel Betacoronavirus subgroup A coronavirus, rabbit coronavirus HKU14, from domestic rabbits". Journal of Virology. 86 (10): 5481–96. doi:10.1128/JVI.06927-11. PMC 3347282. PMID 22398294.
  8. ^ a b Lau, S. K.; Poon, R. W.; Wong, B. H.; Wang, M.; Huang, Y.; Xu, H.; Guo, R.; Li, K. S.; Gao, K.; Chan, K. H.; Zheng, B. J.; Woo, P. C.; Yuen, K. Y. (2010). "Coexistence of different genotypes in the same bat and serological characterization of Rousettus bat coronavirus HKU9 belonging to a novel Betacoronavirus subgroup". Journal of Virology. 84 (21): 11385–94. doi:10.1128/JVI.01121-10. PMC 2953156. PMID 20702646.
  9. ^ Zhang, Wei; Zheng, Xiao-Shuang; Agwanda, Bernard; Ommeh, Sheila; Zhao, Kai; Lichoti, Jacqueline; Wang, Ning; Chen, Jing; Li, Bei; Yang, Xing-Lou; Mani, Shailendra; Ngeiywa, Kisa-Juma; Zhu, Yan; Hu, Ben; Onyuok, Samson Omondi; Yan, Bing; Anderson, Danielle E.; Wang, Lin-Fa; Zhou, Peng; Shi, Zheng-Li (24 October 2019). "Serological evidence of MERS-CoV and HKU8-related CoV co-infection in Kenyan camels". Emerging Microbes & Infections. 8 (1): 1528–1534. doi:10.1080/22221751.2019.1679610. PMC 6818114. PMID 31645223.
  10. ^ a b Cotten, Matthew; Lam, Tommy T.; Watson, Simon J.; Palser, Anne L.; Petrova, Velislava; Grant, Paul; Pybus, Oliver G.; Rambaut, Andrew; Guan, Yi; Pillay, Deenan; Kellam, Paul; Nastouli, Eleni (2013-05-19). "Full-Genome Deep Sequencing and Phylogenetic Analysis of Novel Human Betacoronavirus - Vol. 19 No. 5 - May 2013 - CDC". Emerging Infectious Diseases. 19 (5): 736–42B. doi:10.3201/eid1905.130057. PMC 3647518. PMID 23693015.
  11. ^ a b Woo, Patrick C. Y.; Huang, Yi; Lau, Susanna K. P.; Yuen, Kwok-Yung (2010-08-24). "Coronavirus Genomics and Bioinformatics Analysis". Viruses. 2 (8): 1804–1820. doi:10.3390/v2081803. ISSN 1999-4915. PMC 3185738. PMID 21994708. In all members of Betacoronavirus subgroup A, a haemagglutinin esterase (HE) gene, which encodes a glycoprotein with neuraminate O-acetyl-esterase activity and the active site FGDS, is present downstream to ORF1ab and upstream to S gene (Figure 1).
  12. ^ "ECDC Rapid Risk Assessment - Severe respiratory disease associated with a novel coronavirus" (PDF). 19 Feb 2013. Retrieved 22 Apr 2014.
  13. ^ Antonio C. P. Wong, Xin Li, Susanna K. P. Lau, Patrick C. Y. Woo: Global Epidemiology of Bat Coronaviruses, in: Viruses. 2019 Feb; 11(2): 174, doi:10.3390/v11020174
  14. ^ Woo, P. C.; Huang, Y.; Lau, S. K.; Yuen, K. Y. (2010). "Coronavirus genomics and bioinformatics analysis". Viruses. 2 (8): 1804–20. doi:10.3390/v2081803. PMC 3185738. PMID 21994708.
  15. ^ Huang, C; Qi, J; Lu, G; Wang, Q; Yuan, Y; Wu, Y; Zhang, Y; Yan, J; Gao, GF (1 November 2016). "Putative Receptor Binding Domain of Bat-Derived Coronavirus HKU9 Spike Protein: Evolution of Betacoronavirus Receptor Binding Motifs". Biochemistry. 55 (43): 5977–5988. doi:10.1021/acs.biochem.6b00790. PMID 27696819.
  16. ^ Walls, Alexandra C.; Tortorici, M. Alejandra; Bosch, Berend-Jan; Frenz, Brandon; Rottier, Peter J. M.; DiMaio, Frank; Rey, Félix A.; Veesler, David (8 February 2016). "Cryo-electron microscopy structure of a coronavirus spike glycoprotein trimer". Nature. 531 (7592): 114–117. Bibcode:2016Natur.531..114W. doi:10.1038/nature16988. PMC 5018210. PMID 26855426.
  17. ^ Letko, Michael; Munster, Vincent (22 January 2020). "Functional assessment of cell entry and receptor usage for lineage B β-coronaviruses, including 2019-nCoV". bioRxiv 915660.

External linksEdit