Epigenetic repression of antiviral genes by SARS-CoV-2 NSP1.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evades the innate immune machinery through multiple viral proteins, including nonstructural protein 1 (NSP1). While NSP1 is known to suppress translation of host mRNAs, the mechanisms underlying its immune evasion properties remain elusive. By integrating RNA-seq, ribosome footprinting, and ChIP-seq in A549 cells we found that NSP1 predominantly represses transcription of immune-related genes by favoring Histone 3 Lysine 9 dimethylation (H3K9me2). G9a/GLP H3K9 methyltransferase inhibitor UNC0638 restored expression of antiviral genes and restricted SARS-CoV-2 replication. Our multi-omics study unravels an epigenetic mechanism underlying host immune evasion by SARS-CoV-2 NSP1. Elucidating the factors involved in this phenomenon, may have implications for understanding and treating viral infections and other immunomodulatory diseases.