Identification, characterization and expression analysis of circRNA encoded by SARS-CoV-1 and SARS-CoV-2

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• Virus-encoded circular RNAs (circRNAs) play roles in immune responses and can serve as therapeutic targets or biomarkers.
• Coronaviruses SARS-CoV-1 and SARS-CoV-2 (SARS-CoV-1/2) are highly contagious and lethal, but their encoded circRNAs remain largely uncharacterized.

Purpose of the Study:

• To investigate whether SARS-CoV-1/2 encode circRNAs.
• To characterize the features and functions of these viral circRNAs.

Main Methods:

• Utilized RNA sequencing data from SARS-CoV-1 and SARS-CoV-2 infections.
• Employed circRNA identification tools (circRNA_finder, find_circ, CIRI2) for detection.
• Performed circRNA identification and characterization using CirRNAPL.
• Conducted target gene prediction and functional enrichment analysis.

Main Results:

• Identified 151 circRNAs in SARS-CoV-1 and 470 in SARS-CoV-2, indicating higher encoding ability in SARS-CoV-2.
• Observed that only a few viral circRNAs exhibited high expression levels, with the positive strand producing more abundant circRNAs.
• Found associations between viral circRNAs and cancer, suggesting a role in regulating host cell functions.

Conclusions:

• SARS-CoV-1/2 encode circRNAs with distinct characteristics and functions.
• Viral circRNAs are implicated in cancer and host cell regulation.
• This research provides a foundational resource for understanding coronavirus circRNA mechanisms.