Fig. 6.

Test for the stimulatory effect of PCNA proteins on DNA polymerase delta activity. The polymerase activity assay was performed using poly(dA)/oligo(dT) as a template, [³H]TTP and 0.54 units of human DNA polymerase delta either alone or in the presence of 5 μg of the tested proteins: human PCNA (HsPCNA), PcPCNA1, PcPCNA-like1 or BSA (negative control). In addition, these proteins were assayed in the absence of human DNA polymerase delta. The radioactivity of the acid-precipitable material, measured in cmp, was then converted to pmol of [³H]TMP incorporated during 30 min of the reaction.