Activation of protein kinase C inhibits adenovirus VA gene transcription in vitro.

We report here that activation of protein kinase C (PKC) results in the inhibition of adenovirus virus-associated (VA) gene transcription in vitro. The involvement of PKC in this inhibition is supported by the fact that the addition of PKC inhibitors to transcription reactions in which the PKC cofactor phosphatidyl serine (PS) was present resulted in increased levels of transcription compared to those in reactions in which PKC activity was stimulated in the absence of PKC inhibitors. Furthermore, based on these in vitro studies we propose that the inhibition of VA gene transcription is possibly due to the inability of the VA gene to form an active transcription complex following the activation of PKC. This conclusion was drawn from in vitro data which demonstrated that PS stimulation of endogenous PKC present in cell extracts resulted in failure to isolate a fully initiated, stable transcription complex.