The life cycle of human papillomaviruses

The life cycle of human papillomaviruses (HPV) is dependent on epithelial differentiation and is regulated by a number of cellular proteins. HPVs infect keratinocytes in the basal layer of the epithelium, and upon cell division, one daughter cell migrates to upper layers while undergoing differentiation. Differentiation triggers the productive phase of the viral life cycle, including viral DNA amplification, late gene expression and virion assembly. Through the actions of viral proteins, infected cells remain active in the cell cycle, creating an environment conducive to late viral events and the production of progeny virions.