The Roles of APOBEC-mediated RNA Editing in SARS-CoV-2 Mutations, Replication and Fitness

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• SARS-CoV-2 mutations drive new strains, impacting infectiousness and vaccine efficacy.
• Viral RNA mutations originate from polymerase errors and host factor modifications.
• A C-to-U mutation bias in SARS-CoV-2 suggests a role for host APOBEC cytosine deaminases.

Approach:

• Experimental validation of APOBEC3A, APOBEC1, and APOBEC3G editing activity on SARS-CoV-2 RNA.
• Assessment of viral replication and progeny production in Caco-2 cells expressing APOBECs.
• Analysis of mutation patterns and genomic RNA structure to predict APOBEC-mediated edits.

Key Points:

• APOBEC3A, APOBEC1, and APOBEC3G experimentally edit SARS-CoV-2 RNA, inducing C-to-U mutations.
• APOBEC expression does not inhibit, but rather enhances, SARS-CoV-2 replication and propagation.
• SARS-CoV-2 appears to leverage APOBEC-mediated mutations for viral fitness and evolution.

Conclusions:

• Host APOBECs actively edit SARS-CoV-2 RNA, contributing to viral evolution.
• The SARS-CoV-2 genome may utilize APOBEC-mediated mutations for adaptation and the emergence of new strains.
• Predicting viral mutations is possible based on APOBEC motifs (UC/AC) and RNA structure.