Transforming protein which induces the development of dermal sarcomas. Induces positive and negative regulation of transcription from host and viral promoters by interacting with various cellular factors involved in protein transcription regulation. Interacts (via transcription activation domain) with host TAF9 in vitro. Interacts with host CDK3 and CDK8. Concentrated in interchromatin granule clusters and perichromatin fibrils. Contains two known functional domains, a cyclin box motif and a carboxy terminal transcription activation domain. Belongs to the cyclin family.