Viral encoded cyclins

Cyclins are known effectors of cellular proliferation. While originally considered as the product of cellular genes, it is now clear that representatives of this class of proteins can be encoded by certain viruses. One of these viruses is HHV-8, a gamma herpesvirus implicated as a causative agent of Kaposi's Sarcoma and lymphomas in humans. The significance of the virally encoded cyclin proteins in viral propagation is as yet unclear. However, the fact that deregulation of cellular cyclin expression is a known event in tumour development suggests that the virally encoded cyclins could be part of a mechanism utilised by these viruses to induce tumour formation.