DNA repair in nuclei isolated from HeLa cells

We have studied the DNA repair synthesis in HeLa cell isolated nuclei in presence of aphidicolin, which selectively inhibits DNA polymerase alpha but not DNA polymerases beta and gamma. The drug strongly depresses the DNA synthesis rate both in vivo and in the subcellular system but seems not to interfere with DNA repair. The enhancement in nucleotide incorporation by isolated nuclei after UV-irradiation is observed only in the presence of ATP.