BFV activates the NF-κB pathway through its transactivator (BTas) to enhance viral transcription

Multiple families of viruses have evolved sophisticated strategies to regulate nuclear factor-kappa B (NF-kappa B) signaling, which plays a pivotal role in diverse cellular events, including virus-host interactions. In this study, we report that bovine foamy virus (BFV) is able to activate the NF-kappa B pathway through the action of its transactivator, BTas. Both cellular IKK beta and I kappa B alpha also participate in this activation. In addition, we demonstrate that Bias induces the processing of p100, which implies that Bias can activate NF-kappa B through a noncanonical pathway as well. Co-immunoprecipitation analysis shows that BTas interacts with IKK catalytic subunits (IKK alpha and IKK beta), which may be responsible for regulation of IKK kinase activity and persistent NF-kappa B activation. Furthermore, our results indicate that the level of Bias-mediated LTR transcription correlates with the activity of cellular NF-kappa B. Together, this study suggests that BFV activates the NF-kappa B pathway through Bias to enhance viral transcription. (C) 2010 Elsevier Inc. All rights reserved.