NS1-BP interacts with RNA-binding proteins, RNA polymerase II, and influenza A virus polymerase.

<p>(A) Top panel, HeLa cell lysates were immunoprecipitated with control IgG or NS1-BP antibodies. Interacting proteins were resolved by SDS-PAGE and identified by mass spectrometry. Bottom panel, A549 cells were treated with non-targeting or NS1-BP siRNAs (1, 2, and 3) for 48 h. Cell extracts were subjected to immunoblot analysis, which shows NS1-BP knockdown. β-actin served as loading control. (B) Immunoprecipitation was performed with control IgG or anti-NS1-BP antibodies, in the absence or presence of RNase A. Western blots were then performed with the depicted antibodies, selected based on the proteins identified in A. (C) A549 cells were mock-infected or infected with influenza virus at MOI 5 for 5 h. Cells were lysed and subjected to size exclusion chromatography. The fractions were concentrated by TCA precipitation and analyzed by western blot with the indicated antibodies. (D) A549 cells were mock-infected or infected with influenza virus (A/WSN/33) at MOI 2 for 16 h. Cell lysates were immunoprecipitated with control IgG or anti-NS1-BP antibodies. Western blots were performed with the depicted antibodies.