Nucleotide excision repair by extracts of human fetal hepatocytes

Human hepatocytes are particularly exposed to genotoxins, and nucleotide excision repair (NER) in these cells is essential for the maintenance of genome integrity. To characterize NER under conditions that closely resemble the pathway in vivo, we report the preparation and use of primary human fetal liver extracts to define the repair of a 1,3-intrastrand d(GpTpG)-cisplatin DNA lesion. Endonucleolytic cleavage at unique sites on either side of the adduct occurs at similar positions to the dominant NER incisions that have been reported for HeLa extracts. However, incisions effected by primary hepatocyte extracts are more precise as no secondary cleavage sites are detected 5' and 3' to the cisplatin lesion.