Cloning of the p53-dependent origin of cellular DNA replication

We have recently reported that the c-myc protein may promote cellular DNA replication by binding to the origin of DNA replication (ori) and that an origin of human DNA replication which can autonomously replicate in human cells was cloned as a binding sequence of c-myc protein (Iguchi-Ariga et al., 1987). Here we report that cellular tumor antigen p53 may also participate in cellular DNA replication and another origin of DNA replication was cloned as a possible p53-binding sequence. The sequence could autonomously replicate in Raji cells which express p53 at a high level but not in HL-60 cells in which the coding gene for p53 is largely deleted. Little homology of the sequences was found between c-myc protein-binding ori and p53-binding ori. This suggests that c-myc protein and p53 may independently recognize different ori in chromosomal DNA.