Microinjection of normal cell extracts into Fanconi anemia fibroblasts corrects defective scheduled DNA synthesis recovery after 8-methoxypsoralen plus UVa treatment.

Fanconi anemia (FA) cells show an increased sensitivity to 8-methoxypsoralen (8-MOP) plus UVa treatment; after an initial reduction of their semiconservative DNA synthesis rate, they do not recover like normal cells. We microinjected extracts from normal cells into FA fibroblasts from complementation group A and determined semiconservative DNA synthesis rates by autoradiography; the hampered recovery phase was completely restored.