FIG. 1.

SV40 TAg constructs. The J domain is contained within the first 82 residues and includes the conserved HPD (residues 42 to 44). The point substitution mutant H42Q inactivates the J domain function of TAg (6, 68). The LXCXE motif is present in residues 103 to 107. The K1, C105G, and PVU-1 mutations disrupt binding to all pRB family members (76). The HQ-K1 mutant contains inactivating mutations in the J domain and LXCXE motif. The dl434-444 mutant disrupts the ability of TAg to bind to p53 (40). T1-350 contains the first 350 amino acids of TAg. T1-135 contains the first 131 amino acids of TAg plus 4 additional residues (79). All TAg constructs were expressed as cDNAs in a pSG5 plasmid under an SV40 promoter.