IFN-kappa inhibits HPV31 transcription by inducing Sp100 proteins

Using doxycycline-inducible IFN-kappa expression in CIN612-9E cells, which maintain extrachromosomally replicating HPV31 genomes, we demonstrate that IFN-kappa inhibits the growth of these cells and reduces viral transcription and replication. Interestingly, the initiation of viral early transcription was already inhibited 4-6h after IFN-kappa expression. This was also observed with recombinant IFN-beta suggesting a common mechanism of IFNs. RNA-seq analysis identified 1367 IFN-kappa regulated genes of which 221 were modulated >2-fold. The majority of those (71%) matched known ISGs confirming that IFN-kappa acts as a bona fide type I IFN in hr-HPV-positive keratinocytes. RNAi and co-transfection experiments indicate that the inhibition of viral transcription is mainly due to the induction of Sp100 proteins by IFN-kappa. Overall design: CIN612-9E/pInd-IFN-kappa were induced for 4h with 1µg/ml doxycyclin or not. Three biological replicates were analyzed.

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Habiger C, Jäger G, Walter M, Iftner T, Stubenrauch F