SARS-CoV-2 ORF10 Products

SARS-CoV-2 Open Reading Frame 10 (ORF10) is one of the nine downstream accessory protein open reading frames of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19 (1). SARS-CoV-2 ORF10 is the smallest accessory protein at 38 amino acids (aa) in length with a theoretical molecular weight of 4.4 kDa (1, 2). ORF10 is proposed to be unique to SARS-CoV-2, however it likely evolved from mutations in other coronaviruses (1, 3). Interestingly, the ORF10 of SARS-CoV-2 has 97.3% homology to Pangolin-CoV ORF10, but there are still prominent differences in properties such as protein structure, solubility, and mutational diversification (4).

Functionally, SARS-CoV-2 ORF10 is suggested to interact with the Cullin 2 RING E3 ligase complex, indicating that ORF10 might promote viral pathogenesis by taking over the ubiquitination machinery (4, 5). Additionally, the SARS-CoV-2 ORF10 gene appears to be differentially expressed based on COVID-19 severity. For example, ORF10 appears to be highly expressed in the infected cells from severe cases while it is either lowly expressed or not detectable in cells infected from moderate cases (6). Therefore, ORF10 expression could be indicative of COVID-19 progression (6).

References

1. Michel, C. J., Mayenr, C., Poch, O., & Thompson, J. D. (2020). Characterization of accessory genes in coronavirus genomes. Virology journal. https://doi.org/10.1186/s12985-020-01402-1

2. Uniprot (A0A6B9W2G5)

3. Yoshimoto F. K. (2020). The Proteins of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2 or n-COV19), the Cause of COVID-19. The protein journal. https://doi.org/10.1007/s10930-020-09901-4

4. Hassan, S., Attrish, D., Ghosh, S., Choudhury, P., Uversky, V., Uhal, B., Lundstrom, K., Rezaei, N., Aljabali, A., Seyran, M., et al. (2020). Notable sequence homology of the ORF10 protein introspects the architecture of SARS-COV-2. bioRxiv. 10.1101/2020.09.06.284976.

5. Ahmadpour, D., & Ahmadpoor, P. (2020). How the COVID-19 Overcomes the Battle? An Approach to Virus Structure. Iranian journal of kidney diseases.

6. Liu, T., Jia, P., Fang, B., & Zhao, Z. (2020). Differential Expression of Viral Transcripts From Single-Cell RNA Sequencing of Moderate and Severe COVID-19 Patients and Its Implications for Case Severity. Frontiers in microbiology. https://doi.org/10.3389/fmicb.2020.603509