Roscovitine Inhibits Activation of Promoters in Herpes Simplex Virus Type 1 Genomes Independently of Promoter-Specific Factors

Abstract

Flavopiridol, roscovitine, and other inhibitors of Cyclin-Dependent Kinases (CDK) inhibit the replication of a variety of viruses in vitro while proving nontoxic in human clinical trials of their effects against cancer. Consequently, these and other Pharmacological CDK inhibitors (PCIs) have been proposed as potential antivirals. Flavopiridol potently inhibits all tested CDKs and inhibits the transcription of most cellular and viral genes. In contrast, roscovitine and other purine PCIs inhibit with high potency only CDK1, CDK2, CDK5, and CDK7, and they specifically inhibit the expression of viral but not cellular genes. The levels at which purine PCIs inhibit gene expression are unknown, as are the factors which determine their specificity for expression of viral but not cellular genes. We show herein that roscovitine prevents the initiation of transcription of herpes simplex virus type 1 (HSV-1) genes but has no effect on transcription elongation. We further show that roscovitine does not inhibit the initiation or elongation of cellular transcription and that its inhibitory effects are specific for promoters in HSV-1 genomes. Therefore, we have identified a novel biological activity for PCIs, i.e., their ability to prevent the initiation of transcription. We have also identified genome location as one of the factors that determine whether the transcription of a given gene is inhibited by roscovitine. The activities of roscovitine on viral transcription resemble one of the antiherpesvirus activities of alpha interferon and could be used as a model for the development of novel antivirals. The genome-specific effects of roscovitine may also be important for its development against virus-induced cancers.

CDK9 inhibitor FIT-039 prevents replication of multiple DNA viruses

“…Accordingly, FIT-039 reduced the expression levels of HSV-1 IEGs and early and late genes ( Figure 2B and Supplemental Figure 4). IEGs are transcribed immediately after the viral infection, and their encoded proteins regulate the transcription of early and late viral genes (30). These results indicated that the antiviral mechanism may be attributed to the inhibition of the viral transcription through suppression of the CTD phosphorylation of RNA polymerase II.…”

Rigid amphipathic fusion inhibitors, small molecule antiviral compounds against enveloped viruses

“…2 D and E). We therefore tested entry using reporter cells containing a red fluorescence protein (RFP) gene driven by a VP16-responsive promoter (35). VP16 is in the tegument of HSV-1 virions, a protein layer underneath the envelope but outside the capsid.…”

“…Vero Clone 57 cells express RFP under the control of the HSV-1 ICP0 promoter (35). Huh7.5 cells were obtained from C. Rice (The Rockefeller University, New York, NY).…”

Emerin Is Hyperphosphorylated and Redistributed in Herpes Simplex Virus Type 1-Infected Cells in a Manner Dependent on both UL34 and US3

“…These authors found that emerin hyperphosphorylation depended upon US3 in HSV-2-infected cells and that it could be inhibited by an inhibitor of the cyclin-dependent kinase CDK1. The dependence on CDK1 activity is interesting, since inhibitors of CDKs, including CDK1, inhibit multiple steps in the virus life cycle (8,11,28,(56)(57)(58), and a dominant-negative CDK1 inhibits viral-DNA replication and late-gene expression (1). CDK1 inhibition may depress expression of late genes, and the CDK1 dependence of emerin phosphorylation may reflect lower UL34 expression and recruitment of PKC␦.…”