Antisense and mutated cDNA of the human excision repair gene ERCC-1 were overexpressed in repair efficient HeLa cells by means of an Epstein-Barr-virus derived CDNA expression vector. Whereas antisense RNA did not influence the survival of the transfected cells, a mutated cDNA generating an ERCC-1 protein with two extra amino acids in a conserved region of its C-terminal part resulted in a significant sensitization of the HeLa transfectants to mitomycin C-induced damage. These results suggest that overexpression of the mutated ERCC-1 protein interferes with proper functioning of the excision repair pathway in repair proficient cells and is compatible with a model in which the mutated ERCC-1 protein competes with the wildtype polypeptide for a specific step in the repair process or for occupation of a site in a repair complex. Apparently, this effect is more pronounced for mitomycin C induced crosslink repair than for UV-induced DNA damage.

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Keywords *Mutation, 0 (Proteins), 0 (RNA, Antisense), 50-07-7 (Mitomycin), Amino Acid Sequence, Animals, Cloning, Molecular, DNA Repair/*genetics, EC 3.1.- (ERCC-1 protein, human), Gene Expression Regulation, Hela Cells/drug effects/radiation effects, Human, Mice, Mitomycin/pharmacology, Molecular Sequence Data, Phenotype, Proteins/*genetics, RNA, Antisense/metabolism, Sequence Alignment, Support, Non-U.S. Gov't, Transfection, Ultraviolet Rays
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Belt, P.B.G.M., van Oostenrijk, M.F., Odijk, H., Hoeijmakers, J.H.J., & Backendorf, C.M.P.. (1991). Induction of a mutant phenotype in human repair proficient cells after overexpression of a mutated human DNA repair gene.. Nucleic Acids Research, 19, 5633–5637. Retrieved from