SV40 antigen and tumor suppressor - stock illustration

SV40 antigen and tumour suppressor. Molecular model of the simian virus (SV40) large T antigen bound to a retinoblastoma tumour suppressor (Rb). Large T antigens play a role in regulating the viral life cycle of the polyomaviridae viruses, such as SV40. SV40 is potentially tumour-causing in primates and humans. Rb proteins encourage normal cell cycles, thus preventing the formation of tumours. When the large T antigen binds to Rb, the tumour suppressor's action is blocked, and the development of malignant tumours becomes more likely.