The Regulation of Human Papillomavirus Gene Expression by the E2 Protein: Keeping a Finger in Every Pie
Sheila Graham and Kevin L. Gaston
from: Small DNA Tumour Viruses (Edited by: Kevin Gaston). Caister Academic Press, U.K. (2012)
The human papillomavirus (HPV) genome is around 8000 base pairs in length and it encodes only eight proteins, a limited number of protein isoforms and no known microRNAs. Despite this relative paucity of genes and gene products these viruses are highly successful. Over 120 HPV types have been identified and they are the causative agents of a wide range of endemic prevalent diseases such as genital warts and common warts as well as rarer but much more serious diseases such as cervical cancer and penile cancer. In order to complete its life cycle HPV must harness the activities of the host cells to transcribe, translate and replicate the viral genome while simultaneously evading a battery of host defences. To facilitate these processes virally encoded non-structural proteins interact with a plethora of host cell proteins and manipulate many host cell regulatory pathways. This review focuses on the regulation of viral gene expression and in particular the diverse roles played by the viral E2 protein and its multiple cellular and viral binding proteins. E2 appears to function as a "master regulator", controlling viral gene expression at many levels while also enabling viral DNA replication and ensuring equal viral genome segregation during cell division. This impressive feat of multitasking is achieved via a network of E2-interacting proteins that includes almost all of the other viral proteins and a wide range of cellular partners read more ...