Examination of NF-κB p50 and p65 levels and TNF-α-induced IκBα degradation in HTNV N-expressing cells. A549 cells were transfected with 500 ng of pWRG7077-Empty, pWRG7077-HTNV-S, or pWRG7077-HTNV-M for 24 h. To induce the degradation of IκBα, cells were treated with 50 ng/ml of TNF-α for 15 min, and lysates were prepared for immunoblotting. For uninduced samples, cells were left untreated. Proteins were transferred onto PVDF membranes and probed with antibodies against IκBα, p50, p65, HTNV N protein, or GAPDH. +, with; −, without.