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Molecular cloning and biological characterization of a human gene, ERCC2, that corrects the nucleotide excision repair defect in CHO UV5 cells

Journal Article · · Mol. Cell. Biol.; (United States)
DOI:https://doi.org/10.1128/MCB.8.3.1137· OSTI ID:5131564

The UV-sensitive Chinese hamster ovary (CHO) cell line UV5, which is defective in the incision step of nucleotide excision repair, was used to identify and clone a complementing human gene, ERCC2, and to study the repair process. Genomic DNA from a human-hamster hybrid cell line was sheared and cotransferred with pSV2gpt plasmid DNA into UV5 cells to obtain five primary transformants. Transfer of sheared DNA from one primary transformant resulted in a secondary transformant expressing both gpt and ERCC2. The human repair gene was identified with a probe for Alu-family repetitive sequences. For most primary, secondary, and cosmid transformants, survival after UV exposure showed a return to wild-type levels of resistance. The levels of UV-induced mutation at the part locus for secondary and cosmid transformants varied from 50 to 130% of the wild-type level. Measurements of the initial rate of UV-induced strand incision by alkaline elution indicated that, whereas the UV5 rate was 3% of the wild-type level, rates of cosmid-transformed lines were similar to that of the wild type, and the secondary transformant rate was about 165% of the wild-type rate. Analysis of overlapping cosmids determined that ERCC2 is between 15.5 and 20 kilobases and identified a closely linked gpt gene. Cosmids were obtained with functional copies of both ERCC2 and gpt. ERCC2 corrects only the first of the five CHO complementation groups of incision-defective mutants.

Research Organization:
Biomedical Sciences Div., Lawrence Livermore National Lab., P.O. Box 5507, Livermore, CA (US)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
5131564
Journal Information:
Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 8:3; ISSN MCEBD
Country of Publication:
United States
Language:
English