The yeast two-hybrid system reveals no interaction between p73 alpha and SV40 large T-antigen

SV40 and/ or DNA sequences indistinguishable from SV40 have been detected i n several types of human tumours. The oncoprotein of Simian virus 40, SV40 large T-antigen (Tag), is known to bind and inactivate tumour suppressor pr oteins, such as members of the retinoblastoma family and p53, thereby promo ting cell transformation. In this study, we used the yeast two-hybrid syste m to investigate whether the Simian virus 40 (SV40) large T-antigen is able to interact with p73, a noval discovered putative tumour suppressor, that is homologous both structurally and functionally to p53. The yeast two-hybr id system is a genetic method to detect protein-protein-interactions in viv o. Our results suggest that the SV40 large T-antigen is not able to bind p7 3 in yeast although both proteins are expressed in the transformed yeast st rain as was shown by western blot analysis.