CPSF6 and viral infectious disease: Furthermore, higher levels of secreted IFN-β were detected in culture supernatant from CPSF6-/- A549 and L929 cells (Figs 6C–6E and S6B–S6D), and this increasing trend was abolished by ectopic expression of CPSF6 (Fig 6C–6E), demonstrating that CPSF6 deficiency promoted IFN-I responses against viral infection by increasing IFN-β production and ISG expression.