Detection of DNA replicase activity in rat thymoma cells

A DNA polymerase which was active with unprimed poly(dC) as a template was detected in the DNA polymerase alpha fraction from rat thymoma tissue. The activity was dependent on rGTP and associated with ribonucleotide polymerizing activity. The activity was partially sensitive to aphidicolin and dideoxy GTP and resistant to alpha-amanitin. Thus, this is a rat "replicase" which is very similar to that found in mouse cells. The replicase activity with poly(dT) or phage fd single stranded circular DNA was greatly enhanced by the mouse replicase-stimulating factor beyond the species difference.