CRISPR/Cas9-based knockout strategy elucidates components essential for type 1 interferon signaling in human HeLa cells

Publication date: Available online 15 June 2019Source: Journal of Molecular BiologyAuthor(s): Victoria Urin, Maya Shemesh, Gideon SchreiberAbstractType I interferons (IFNs) have a central role in innate and adaptive immunities, proliferation, and cancer surveillance. How IFN binding to its specific receptor, the interferon α and β receptor (IFNAR), can drive such variety of processes is an open question. Here, to systematically and thoroughly investigate the molecular mechanism of IFN signaling, we used a CRISPR/Cas9-based approach in a human cell line (HeLa) to generate knockouts (KOs) of the genes participating in the type 1 IFN signaling cascade. We show that both IFNAR chains (IFNAR1 and IFNAR2) are absolutely required for any IFN-induced signaling. Deletion of either signal transducer and activator of transcription 1 (STAT1) or STAT2 had only a partial effect on IFN-induced antiviral activity or gene induction. However, the deletion of both genes completely abrogated any IFN-induced activity. So did a double STAT2–interferon regulatory factor 1 (IRF1) KO and to a large extent a STAT1 KO together with IRF9 knockdown. KO of any of the STATs had no effect on the phosphorylation of other STATs, indicating that they bound IFNAR independently. STAT3 and STAT6 phosphorylation were fully induced by type 1 IFN in the STAT1–STAT2 KO, but did not promote gene induction. Moreover, STAT3 KO did not affect type 1 IFN–induced gene or protein expression. Type 1 IFN also did not ...
Source: Journal of Molecular Biology - Category: Molecular Biology Source Type: research