The basal and the mutagen-induced levels of ADP-ribosyl transferase activity are not modified in Fanconi's anemia cells.

The activity of ADP-ribosyl transferase, an enzyme thought to be involved in several basic functions of the chromatin and in DNA repair, has been investigated in normal and Fanconi's anemia (FA) cells. Fibroblasts and lymphoblasts treated with alkylating (dimethyl sulfate) or cross-linking (mitomycin C, psoralen plus UVA) agents were compared to untreated cells. The basal level of the enzymatic activity was found to be the same in normal and FA cells and the enzymatic response to treatments with DNA-damaging agents was similar in both cell types. Consequently it is unlikely that the molecular defect in FA cells is due to a decreased activity in ADP-ribosyl transferase.