Complementation of the xeroderma pigmentosum DNA repair synthesis defect with Escherichia coli UvrABC proteins in a cell-free system.
A newly developed cell-free system was used to study DNA repair synthesis carried out by extracts from human cell lines in vitro. Extracts from a normal human lymphoid cell line and from cell lines established from individuals with hereditary dysplastic nevus syndrome perform damage-dependent repair synthesis in plasmid DNA treated with cis- or trans-diamminedichloro-platinum(II) or irradiated with ultraviolet light. Cell extracts of xeroderma pigmentosum origin (complementation groups A, C, D, and G) are deficient in DNA repair synthesis. When damaged plasmid DNA was pretreated with purified Escherichia coli UvrABC proteins, xeroderma pigmentosum cell extracts were able to carry out DNA repair synthesis. The ability of E. coli UvrABC proteins to complement xeroderma pigmentosum cell extracts indicates that the extracts are deficient in incision, but can carry out later steps of repair. Thus the in vitro system provides results that are in agreement with the incision defect found from studies of xeroderma pigmentosum cells.
Imperial Cancer Research Fund, Clare Hall Laboratories, Herts, UK.
J
J
Hansson
L
L
Grossman
T
T
Lindahl
R D
RD
Wood
D002474:Cell-Free System; D002945:Cisplatin; D004249:DNA Damage; D004260:DNA Repair; D004416:Dysplastic Nevus Syndrome / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D006801:Humans; D010957:Plasmids; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000201:enzymology / Q000235:genetics*
D029968:Escherichia coli Proteins; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC; D002945:Cisplatin