Lymphotropic papovavirus transforms hamster cells without altering the amount or stability of p53

Expression of the early regions of several primate polyomaviruses (SV40, BKV, JCV, and LPV) in hamster cells induces transformation, manifested by the ability to grow in soft agar. Hamster cells transformed by SV40 contain complexes between the SV40 T antigen and the cellular tumor suppressor protein p53. We detected analogous complexes between p53 and the BKV T antigen in hamster cells transformed by the BKV early region, where the half life of p53 increased 16-fold. However, neither a LPV-transformed hamster fibroblast cell line [LPV-HE (F); K. K. Takemoto and T. Kanda, 1984, J. Virol. 50, 100-105] nor BHK-21 cells transformed by the LPV early region contained detectable complexes between the LPV T antigen and p53, nor was the stability of p53 in LPV transformed BHK-21 cells altered. Association between hamster p53 and the LPV T antigen expressed as glutathione S-transferase fusion protein could not be detected in vitro. These data indicate that alteration of the amount or stability of p53 is not required for transformation of hamster cells by LPV. However, as viruses such as SV40 and BKV whose T antigens bind p53 are oncogenic in hamsters, whereas LPV is not, the alteration of p53 amount or stability may be required for tumorigenesis.