ABSTRACT
The transferase activity increases with the dose of inducing agent delivered to the cells, then reaches a plateau. In order to keep the integrity of their genetic material, bacteria and mammalian cells possess a variety of DNA repair mechanisms. Different cDNA clones encoding DNA–damage inducible transcripts have been isolated from rodent cells and from human cells. The probes were the Xba I/Bam H1 fragment of the plasmid containing the rat transferase cDNA and the Xba 1/Hind III fragment of the APDG plasmid expressing the rat 3-meAde glycosylase. The role of DNA damage in the induction is also supported by the fact that a greater enhancement of the transferase activity is obtained when the cells are treated with the inducing agent than when they are grown in the presence of a poly(ADP-ribose) synthesis inhibitor, which could act either by interacting with DNA repair or by modifying the DNA structure.
