PMLIV positively regulates IFN-β synthesis.

<p>(A) PMLIV enhances IFN-β synthesis without affecting that of IFN-α, IL8 or TNF-α upon VSV infection. U373MG-EV and U373MG-PMLIV cells were infected with VSV at an MOI of 0.2 for different lengths of time. Total RNA was extracted and mRNAs encoding IFN-α, IFN-β, IL8, TNF-α, and GAPDH were quantified by RT-qPCR. (B) PMLIV positively regulates IFN-β synthesis in cells infected with SeV or transfected with poly(I:C). U373MG-EV and U373MG-PMLIV cells were infected with SeV (40 HAU/ml) or EMCV (MOI of 0.5), or transfected with poly(I:C) (1 µg/ml). HeLa cells transduced with PMLIV-expressing or with noncoding parental (EV) lentiviral vectors were infected with HTLV-1 (HTLV, 600 ng/ml of p19-equivalent), influenza virus (Flu, 40 HAU/ml) or vaccinia virus (Vac, MOI of 2). After 8 h, mRNAs were extracted and IFN-βtranscripts quantified by RT-qPCR. (C) SUMOylation of PMLIV was required for IFN-β induction. U373MG-EV, U373MG-PMLIV, U373MG-PMLIV-3KR, U373MG-PMLIII and U373MG-PMLIII-3KR cells were infected with VSV for 12 h at an MOI of 0.2. Total RNA was extracted and mRNAs encoding IFN-β and GAPDH were quantified by RT-qPCR. Mean values and standard deviations of two independent experiments are shown.