PB1-F2 mediates induction of caspase-3-independent apoptosis in SulCOS1 cells.

<p>SulCOS1 cells were infected with two recombinant PB1-F2-deficient mutant viruses (PB1 G144A and PB1 T120C) and wild-type virus. A, Fluorescent staining of AIF, NP, and nuclei at 7 h postinfection as described in the legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061092#pone-0061092-g002" target="_blank">Figure 2</a>. B–D, SulCOS1 cells were infected with the respective virus as described in the Materials and Methods section. Inhibition of virus-induced apoptosis (B), mitochondrial membrane potential loss (C), and progeny virus production (D) in cells infected with PB1-F2-deficient viruses at 24 h postinfection. The progeny virus titers (± standard deviation) in supernatants are expressed as a relative percentage of those of wild-type virus and are average values of three experiments. Student's t-test was used for statistical analysis compared to no virus in (C) and compared to wild-type virus in (D). **, <i>p</i><0.01.