Betacoronavirus NS7B protein | |||||||||
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Identifiers | |||||||||
Symbol | bCoV_NS7B | ||||||||
Pfam | PF11395 | ||||||||
InterPro | IPR021532 | ||||||||
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ORF7b is a gene found in coronaviruses of the genus Betacoronavirus, which expresses the accessory protein Betacoronavirus NS7b protein. [1] It is a short, highly hydrophobic transmembrane protein of unknown function. [1] [2]
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]
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]
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]
Betacoronavirus NS7B protein | |||||||||
---|---|---|---|---|---|---|---|---|---|
Identifiers | |||||||||
Symbol | bCoV_NS7B | ||||||||
Pfam | PF11395 | ||||||||
InterPro | IPR021532 | ||||||||
|
ORF7b is a gene found in coronaviruses of the genus Betacoronavirus, which expresses the accessory protein Betacoronavirus NS7b protein. [1] It is a short, highly hydrophobic transmembrane protein of unknown function. [1] [2]
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]
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]
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]