[Life cycle of HPV governed by the differentiation program of epithelial cell].

Papillomavirus is a pathogenic virus that induces benign tumor at the infected lesion, and its association with malignant tumor was first identified by R. Shope using animal model. A variety of cancers have been reported to be associated with the infection of human papillomavirus since the report by H. zur Hausen that describes a connection between the HPV infection and cervical cancer. The HPV infection is broadly distributed as a sexually transmitted disease (STD) and recently the initial age diagnosed as the cervical cancer is getting lowered. Because of its clinical importance, the study on HPV has been focused on the oncogenic properties, and the results of which had great impacts on the researches of the tumor suppressors, such as p53 and pRb, and "ubiquiitn-proteasome" pathway. On the other hand, the biological properties of HPV remain mostly disclosed. The lifecycle of HPV is tightly linked to the differentiation program of the target epithelial cell, and this unique property has hampered the study on the HPV replication mechanism. Here we summarized the findings on the HPV lifecycle, including the virus gene functions, the regulation of viral gene expression and replication.