THE RETINOBLASTOMA PROTEIN AND ITS RELATIVES

The retinoblastoma tumor suppressor gene is inactivated in retinoblast omas and a variety of other tumor types. In addition, it is one of sev eral cellular proteins targeted by the transforming proteins of the sm all DNA tumor viruses. At least two other cellular proteins that are t argeted by the viral transforming proteins are structurally and functi onally related to the protein, encoded by the retinoblastoma tumor sup pressor gene. Recent data has described a complex series of interactio ns with cyclins, kinases and transcription factors. It is presumably t hrough these interactions that the retinoblastoma-related proteins exe rt their effects on cellular proliferation.