ORF7b: Difference between revisions
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Revision as of 05:05, 17 September 2021
| Betacoronavirus NS7B protein | |||||||||
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| Identifiers | |||||||||
| Symbol | bCoV_NS7B | ||||||||
| Pfam | PF11395 | ||||||||
| InterPro | IPR021532 | ||||||||
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In molecular biology, Betacoronavirus NS7B protein (also known as ORF7b protein)[1] is a protein expressed by coronaviruses of the Betacoronavirus genus. It is a viral accessory protein expressed from the ORF7b gene. It is a short, highly hydrophobic transmembrane protein of unknown function.[1][2]
Structure
ORF7b protein is a transmembrane protein with a single transmembrane helix whose membrane topology orients the C-terminus in the cytosol.[1] In SARS-CoV, it is 44 amino acid residues and in SARS-CoV-2 it is 43 residues, with about 85% sequence identity.[2]
Expression and localization
ORF7b is an overlapping gene that overlaps ORF7a.[3] The protein is probably expressed from subgenomic RNA through leaky scanning.[1] In SARS-CoV, it is localized to the Golgi apparatus, which requires the transmembrane helix sequence.[1][4] In SARS-CoV-2, it has been reported to associate with the endoplasmic reticulum.[5]
Function
The function of the ORF7b protein is not well characterized. It is not essential for viral replication,[1][3] though there is inconsistent evidence from studies of SARS-CoV on whether its deletion affects replication.[1][6] In SARS-CoV, it has been identified incorporating into virions, suggesting it is a minor viral structural protein.[1][7] A SARS-CoV-2 variant with a deletion mutation in the ORF7b region, resulting in a fusion protein between ORF7b and ORF8, has been identified, of unclear significance.[2][8]
References
- ^ a b c d e f g h Liu, DX; Fung, TS; Chong, KK; Shukla, A; Hilgenfeld, R (September 2014). "Accessory proteins of SARS-CoV and other coronaviruses". Antiviral research. 109: 97–109. doi:10.1016/j.antiviral.2014.06.013. PMC 7113789. PMID 24995382.
- ^ a b c Redondo, Natalia; Zaldívar-López, Sara; Garrido, Juan J.; Montoya, Maria (7 July 2021). "SARS-CoV-2 Accessory Proteins in Viral Pathogenesis: Knowns and Unknowns". Frontiers in Immunology. 12: 708264. doi:10.3389/fimmu.2021.708264. hdl:10261/249329.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b Pekosz, Andrew; Schaecher, Scott R.; Diamond, Michael S.; Fremont, Daved H.; Sims, Amy C.; Baric, Ralph S. (2006). "Structure, Expression, and Intracellular Localization of the SARS-CoV Accessory Proteins 7a and 7b". The Nidoviruses. 581: 115–120. doi:10.1007/978-0-387-33012-9_20.
- ^ Schaecher, Scott R.; Diamond, Michael S.; Pekosz, Andrew (October 2008). "The Transmembrane Domain of the Severe Acute Respiratory Syndrome Coronavirus ORF7b Protein Is Necessary and Sufficient for Its Retention in the Golgi Complex". Journal of Virology. 82 (19): 9477–9491. doi:10.1128/JVI.00784-08.
- ^ Zhang, Jing; Cruz-cosme, Ruth; Zhuang, Meng-Wei; Liu, Dongxiao; Liu, Yuan; Teng, Shaolei; Wang, Pei-Hui; Tang, Qiyi (December 2020). "A systemic and molecular study of subcellular localization of SARS-CoV-2 proteins". Signal Transduction and Targeted Therapy. 5 (1): 269. doi:10.1038/s41392-020-00372-8.
- ^ McBride, Ruth; Fielding, Burtram (7 November 2012). "The Role of Severe Acute Respiratory Syndrome (SARS)-Coronavirus Accessory Proteins in Virus Pathogenesis". Viruses. 4 (11): 2902–2923. doi:10.3390/v4112902.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Schaecher, Scott R.; Mackenzie, Jason M.; Pekosz, Andrew (15 January 2007). "The ORF7b Protein of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) Is Expressed in Virus-Infected Cells and Incorporated into SARS-CoV Particles". Journal of Virology. 81 (2): 718–731. doi:10.1128/JVI.01691-06.
- ^ Su, Yvonne C. F.; Anderson, Danielle E.; Young, Barnaby E.; Linster, Martin; Zhu, Feng; Jayakumar, Jayanthi; Zhuang, Yan; Kalimuddin, Shirin; Low, Jenny G. H.; Tan, Chee Wah; Chia, Wan Ni; Mak, Tze Minn; Octavia, Sophie; Chavatte, Jean-Marc; Lee, Raphael T. C.; Pada, Surinder; Tan, Seow Yen; Sun, Louisa; Yan, Gabriel Z.; Maurer-Stroh, Sebastian; Mendenhall, Ian H.; Leo, Yee-Sin; Lye, David Chien; Wang, Lin-Fa; Smith, Gavin J. D. (25 August 2020). "Discovery and Genomic Characterization of a 382-Nucleotide Deletion in ORF7b and ORF8 during the Early Evolution of SARS-CoV-2". mBio. 11 (4). doi:10.1128/mBio.01610-20.
