N6-methyladenosine modification and METTL3 modulate enterovirus 71 replication

Area of Science:

• Virology
• Molecular Biology
• Epigenetics

Background:

• N6-methyladenosine (m6A) is a prevalent internal RNA modification impacting RNA metabolism.
• m6A's role in viral RNA has been recently explored for viruses like HIV, HCV, and Zika.
• The functional significance of m6A in enterovirus 71 (EV71) infection remains largely uncharacterized.

Purpose of the Study:

• To investigate the role and mechanism of m6A modification in EV71 replication.
• To identify specific m6A sites within the EV71 genome and their functional impact.
• To elucidate the interaction between host m6A regulators and viral components.

Main Methods:

• Analysis of m6A modification in EV71-infected cells.
• Knockdown experiments targeting m6A methyltransferases and demethylases.
• Site-directed mutagenesis of identified m6A sites in the viral genome.
• Co-immunoprecipitation assays to study protein-protein interactions.

Main Results:

• EV71 RNA undergoes m6A modification during infection, affecting host m6A machinery localization.
• Knockdown of m6A methyltransferase reduced EV71 replication, while demethylase knockdown enhanced it.
• Mutating identified m6A sites in the EV71 genome decreased viral replication.
• METTL3 was found to interact with viral 3D polymerase, promoting its sumoylation and ubiquitination, thereby boosting replication.

Conclusions:

• m6A modification is a critical host factor that positively regulates EV71 replication.
• Specific m6A sites within the EV71 genome are essential for efficient viral replication.
• The host m6A writer METTL3 interacts with viral 3D polymerase to enhance its post-translational modification and promote viral replication.