Interaction of adenoviral proteins with pRB and p53.

The transforming gene products of the small DNA tumor viruses subvert host cell growth control mechanisms by binding to specific cell regulatory proteins. These include the retinoblastoma gene product (pRB) and p53. One indication of the pivotal roles played by these regulatory products is the observation that they are each targeted consistently by viruses of several groups, by adenoviruses, the human papillomaviruses, and the papovaviruses. In adenovirus, pRB and p53 are targeted by the E1A and E1B genes, respectively. The genetic probes made possible by manipulation of the virus genes in vitro have helped to illuminate the pathways in which pRB and p53 function. E1A studies have contributed to our current understanding that the retinoblastoma product is one of a family of related proteins, which with associated cyclins and kinases can modulate the activity of the cellular E2F transcription factor. E1B studies have helped explore models of p53 function, including the suggestion that p53, probably through aspects of its transcription regulating activity, can initiate a pathway in which programmed cell death can be invoked to stop unrestricted cell proliferation.