Protein kinases play key roles in the induction by human interferon alpha (IFN-alpha) of specific gene expression and biological activity in various human cell lines. We now report that IFN-alpha increased the 7-kb transcript for the epsilon isotype of protein kinase C (PKC-epsilon) and the cellular content of PKC-epsilon 24 and 48 hr after IFN-alpha addition (a 2-fold and 6-fold increase, respectively). Furthermore, IFN-alpha markedly induced a 4.7-kb transcript that hybridized to a PKC-epsilon-specific, but not to a PKC-eta-specific, cDNA probe. The induction of the 4.7-kb PKC-epsilon-related mRNA by IFN-alpha had the following properties reported for the classical IFN-alpha-stimulated genes: rapid kinetics of induction, high maintained levels in IFN-alpha-sensitive but not in IFN-alpha-resistant cell lines, protein synthesis-independent induction, and high sensitivity to inhibitors of protein tyrosine kinase activity. These results show that the regulation of gene expression by IFN-alpha include not only the classical IFN-alpha-stimulated genes but also the coordinated regulation of two PKC-epsilon-related transcripts that appeared to be highly relevant to the biological actions of IFN-alpha.