N 6 -methyladenosine modification and METTL3 modulate enterovirus 71 replication

Abstract

N 6 -methyladenosine (m 6 A) constitutes one of the most abundant internal RNA modifications and is critical for RNA metabolism and function. It has been previously reported that viral RNA contains internal m 6 A modifications; however, only recently the function of m 6 A modification in viral RNAs has been elucidated during infections of HIV, hepatitis C virus and Zika virus. In the present study, we found that enterovirus 71 (EV71) RNA undergoes m 6 A modification during viral infection, which alters the expression and localization of the methyltransferase and demethylase of m 6 A, and its binding proteins. Moreover, knockdown of m 6 A methyltransferase resulted in decreased EV71 replication, whereas knockdown of the demethylase had the opposite effect. Further study showed that the m 6 A binding proteins also participate in the regulation of viral replication. In particular, two m 6 A modification sites were identified in the viral genome, of which mutations resulted in decreased virus replication, suggesting that m 6 A modification plays an important role in EV71 replication. Notably, we found that METTL3 interacted with viral RNA-dependent RNA polymerase 3D and induced enhanced sumoylation and ubiquitination of the 3D polymerase that boosted viral replication. Taken together, our findings demonstrated that the host m 6 A modification complex interacts with viral proteins to modulate EV71 replication.