ETV7 limits antiviral gene expression and control of SARS-CoV-2 and influenza viruses

Froggatt, Heather M.; Harding, Alfred T.; Heaton, Brook E.; Heaton, Nicholas S.

The type I interferon (IFN) response is an important component of the innate immune response to viral infection. Precise control of interferon responses is critical; insufficient levels of interferon-stimulated genes (ISGs) can lead to a failure to restrict viral spread while excessive ISG activation can result in interferon-related pathologies. While both positive and negative regulatory factors control the magnitude and duration of IFN signaling, it is also appreciated that a number of ISGs regulate aspects of the interferon response themselves. However, the mechanisms underlying these ISG regulatory networks remain incompletely defined. In this study, we performed a CRISPR activation screen to identify new regulators of the type I IFN response. We identified ETS variant transcription factor 7 (ETV7), a strongly induced ISG, as a protein that acts as a negative regulator of the type I IFN response; however, ETV7 did not uniformly suppress ISG transcription. Instead, ETV7 preferentially targeted a subset of known antiviral ISGs. Further, we showed the subset of ETV7-modulated ISGs was particularly important for IFN-mediated control of some viruses including influenza viruses and SARS-CoV-2. Together, our data assign a function for ETV7 as an IFN response regulator and also identify ETV7 as a therapeutic target to increase innate responses and potentiate the efficacy of interferon-based antiviral therapies. One Sentence Summary ETV7 is an interferon-induced, repressive transcription factor that negatively regulates antiviral interferon-stimulated genes essential for controlling influenza virus and SARS-CoV-2 infections.