Related Experiment Video
Updated: Sep 11, 2025
07:55
Generation of Escape Variants of Neutralizing Influenza Virus Monoclonal Antibodies
Published on: August 29, 2017
11.9K
Understanding off-target growth defects introduced to influenza A virus by synonymous recoding.
Colin P Sharp1, Beth H Thompson2, Ananya Ferdous Hoque3
1The Roslin Institute, The University of Edinburgh, Easter Bush Campus, Midlothian EH25 9RG, United Kingdom elly.gaunt@ed.ac.uk colin.sharp@ed.ac.uk.
RNA (New York, N.Y.)
|August 12, 2025
Summary
Engineered high CpG influenza A virus (IAV) replication defects were not due to CpG content but an 8-adenosine tract. This tract caused polymerase slippage, aberrant peptides, and interferon induction, revealing insights into viral attenuation.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- CpG dinucleotides are typically under-represented in RNA virus genomes.
- Increased CpG content can lead to replication defects due to recognition by the Zinc-finger Antiviral Protein (ZAP).
- Previous studies engineered CpG-rich influenza A virus (IAV) with replication defects.
Purpose of the Study:
- To investigate the cause of replication defects in a previously engineered CpG-high IAV mutant.
- To understand the role of compensatory mutations in viral attenuation.
- To explore the impact of an 8-adenosine (8A) tract on viral replication and host response.
Main Methods:
- Genetic manipulation of IAV to create CpG-high and 8A tract variants.
- Analysis of viral replication and attenuation in vitro.
- Assessment of polymerase slippage, aberrant peptide production, and type I interferon induction.
- Comparison of wild-type, CpG-high, and 8A tract viruses.
Main Results:
- The CpG-high IAV mutant's attenuation was not caused by ZAP recognition of CpGs.
- Compensatory mutations creating an 8A tract were responsible for the observed replication defects.
- The 8A tract induced viral polymerase slippage, aberrant peptide synthesis, and type I interferon.
- Restoring wild-type sequence at the 8A tract site abolished attenuation, while introducing the 8A tract into wild-type virus caused attenuation.
Conclusions:
- An 8A tract, not increased CpG content, is the primary driver of attenuation in this engineered IAV.
- Single nucleotide changes can significantly impact viral attenuation and offset engineered barriers.
- Polymerase slippage on polyadenosine tracts may offer insights into viral evolution and the emergence of pathogenic strains.
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