Figure 4: Impact of PB1-F2 expression on the mRNA expression levels of death receptor ligands and receptors. Gene expressions were normalized with the β-actin gene expression level and presented as fold increase relative to nontransfected cell controls. Data asterisks () indicate (p < 0.05) and are calculated relative to the mock vector control which is also represented in the figure. This data is representative of three independent experiments. Error bars represent the ± SEM.