- the oncoproteins are multifunctional
- there is an ever-growing list of cellular interacting proteins
- more than one cellular protein may bind to a given region of the oncoprotein
- there is only limited information on the proteins encoded by the corresponding non-oncogenic papillomaviruses
The perspective of this review is to contrast the activities of the viral E6 and E7 proteins encoded by the oncogenic human PVs (termed high-risk HPVs) to those encoded by their non-oncogenic counterparts (termed low-risk HPVs) in an attempt to sort out viral life cycle-related functions from oncogenic functions. The review emphasizes lessons learned from the cell culture studies of the HPVs causing mucosal/genital tract cancers.