The association of the SV40 large T-antigen (L-Tag), which is expressed early during infection and is essential for viral replication, with Rb, p107, and p130 is attributed to the viral LXCXE residues, which are required but not sufficient in L-Tag-mediated transformation (DeCaprio et al., 1988; Chen and Paucha, 1990; Thompson et al., 1990; Stubdal et al., 1996). The gene discussed is RB1; the disease is infection.