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Updated: Mar 13, 2026
Exploring m6A and m5C Epitranscriptomes upon Viral Infection: an Example with HIV
Published on: March 5, 2022
N6-Methyladenosine in Flaviviridae Viral RNA Genomes Regulates Infection
Nandan S Gokhale1, Alexa B R McIntyre2, Michael J McFadden1
1Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
Abstract:
The RNA modification N6-methyladenosine (m6A) post-transcriptionally regulates RNA function. The cellular machinery that controls m6A includes methyltransferases and demethylases that add or remove this modification, as well as m6A-binding YTHDF proteins that promote the translation or degradation of m6A-modified mRNA. We demonstrate that m6A modulates infection by hepatitis C virus (HCV). Depletion of m6A methyltransferases or an m6A demethylase, respectively, increases or decreases infectious HCV particle production. During HCV infection, YTHDF proteins relocalize to lipid droplets, sites of viral assembly, and their depletion increases infectious viral particles. We further mapped m6A sites across the HCV genome and determined that inactivating m6A in one viral genomic region increases viral titer without affecting RNA replication. Additional mapping of m6A on the RNA genomes of other Flaviviridae, including dengue, Zika, yellow fever, and West Nile virus, identifies conserved regions modified by m6A. Altogether, this work identifies m6A as a conserved regulatory mark across Flaviviridae genomes.
Insights
The RNA modification N6-methyladenosine (m6A) regulates hepatitis C virus (HCV) infection. This epigenetic mark impacts viral particle production and is conserved across Flaviviridae viruses.
Area of Science:
- Virology
- Epigenetics
- Molecular Biology
Background:
- N6-methyladenosine (m6A) is a critical RNA modification regulating RNA fate.
- Cellular machinery, including methyltransferases, demethylases, and YTHDF proteins, controls m6A levels and function.
- The role of m6A in viral infections, particularly hepatitis C virus (HCV), is not fully understood.
Purpose of the Study:
- To investigate the role of m6A in modulating hepatitis C virus (HCV) infection.
- To identify m6A modification sites within the HCV genome.
- To explore the conservation of m6A modification across the Flaviviridae family.
Main Methods:
- Depletion of m6A machinery components (methyltransferases, demethylases, YTHDF proteins) in HCV-infected cells.
- Quantification of infectious HCV particle production.
- Mapping of m6A sites across the HCV genome and other Flaviviridae genomes (dengue, Zika, yellow fever, West Nile virus).
Main Results:
- Depletion of m6A methyltransferases increased, while demethylase depletion decreased, infectious HCV production.
- YTHDF proteins relocalized to lipid droplets during HCV infection, and their depletion enhanced viral particle production.
- Specific m6A modification in the HCV genome increased viral titer without affecting RNA replication; conserved m6A sites were identified in other Flaviviridae.
Conclusions:
- m6A is a key regulator of HCV infection, influencing viral particle production.
- YTHDF proteins play a role in HCV assembly at lipid droplets.
- m6A represents a conserved regulatory mechanism across the Flaviviridae family.
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