ERP127522 PRJEB43558 ena-STUDY-NEW YORK UNIVERSITY SCHOOL OF MEDICINE-09-03-2021-15:24:24:443-1393 Widespread remodeling of the m6A RNA modification landscape by a viral regulator of RNA processing and export. N6-methyladenosine (m6A) is the most abundant internal mRNA modification, contributing to the processing, stability and function of the methylated RNAs. Methylation occurs during pre-mRNA synthesis in the nucleus and requires a core methyltransferase complex consisting of METTL3, METTL14 and WTAP. During herpes simplex virus (HSV-1) infection, cellular gene expression is profoundly suppressed, allowing the virus to monopolize the host transcription and translation apparatus and antagonize antiviral responses. The extent to which HSV-1 uses or manipulates the m6A pathway is not known. Here we show that in primary fibroblasts, HSV-1 orchestrates a striking redistribution of the nuclear m6A machinery that progresses through infection cycle. METTL3 and METTL14 are dispersed into the cytoplasm whereas WTAP remains nuclear. Other regulatory subunits of the methyltransferase complex along with the nuclear m6A-modified RNA binding protein YTHDC1 and nuclear demethylase ALKBH5 are similarly redistributed. These effects require ICP27, a viral regulator of host mRNA processing that mediates the nucleocytoplasmic export of viral late mRNAs. Viral gene expression is initially reduced by siRNA-mediated inactivation of the m6A methyltransferase becoming less impacted after as the infection cycle advances. Redistribution of the nuclear m6A machinery is accompanied by a widescale reduction in the installation of m6A and other RNA modifications on both host and viral mRNAs and provides a new and far-reaching mechanism by which HSV-1 subverts host gene expression to favor viral replication. HSV-1 disruption of host m6A pathway N6-methyladenosine (m6A) is the most abundant internal mRNA modification, contributing to the processing, stability and function of the methylated RNAs. Methylation occurs during pre-mRNA synthesis in the nucleus and requires a core methyltransferase complex consisting of METTL3, METTL14 and WTAP. During herpes simplex virus (HSV-1) infection, cellular gene expression is profoundly suppressed, allowing the virus to monopolize the host transcription and translation apparatus and antagonize antiviral responses. The extent to which HSV-1 uses or manipulates the m6A pathway is not known. Here we show that in primary fibroblasts, HSV-1 orchestrates a striking redistribution of the nuclear m6A machinery that progresses through infection cycle. METTL3 and METTL14 are dispersed into the cytoplasm whereas WTAP remains nuclear. Other regulatory subunits of the methyltransferase complex along with the nuclear m6A-modified RNA binding protein YTHDC1 and nuclear demethylase ALKBH5 are similarly redistributed. These effects require ICP27, a viral regulator of host mRNA processing that mediates the nucleocytoplasmic export of viral late mRNAs. Viral gene expression is initially reduced by siRNA-mediated inactivation of the m6A methyltransferase becoming less impacted after as the infection cycle advances. Redistribution of the nuclear m6A machinery is accompanied by a widescale reduction in the installation of m6A and other RNA modifications on both host and viral mRNAs and provides a new and far-reaching mechanism by which HSV-1 subverts host gene expression to favor viral replication. ENA-FIRST-PUBLIC 2021-07-02 ENA-LAST-UPDATE 2021-07-02