Gene specific damage and repair after treatment of cells with UV and chemotherapeutical agents
- Division of Cancer Treatment, National Cancer Institute, NIH, Bethesda, MD (USA)
The authors have previously demonstrated preferential DNA repair of active genes in mammalian cells. The methodology involves the use of a specific endonuclease or other more direct approaches to create nicks at sites of damage followed by quantitative Southern analysis and probing for specific genes. Initially, they used pyrimidine dimer specific endonuclease to detect pyrimidine dimers after UV irradiation. They now also use the bacterial enzyme ABC excinuclease to examine the DNA damage and repair of a number of adducts other than pyrimidine dimers in specific genes. They can detect gene specific alkylation damage by creating nicks via depurination and alkaline hydrolysis. In our assay for preferential repair, they compare the efficiency of repair in the DHFR gene to that in the 3{prime} flanking, non-coding region to the gene. In CHO cells, UV induced pyrimidine dimers are efficiently repaired from the active DHFR gene, but not from the inactive region. They have demonstrated that the 6-4 photoproducts are also preferentially repaired and that they are removed faster from the regions studied than pyrimidine dimers. Using similar approaches, they find that DNA adducts and crosslinks caused by cisplatinum are preferentially repaired in the active gene compared to the inactive regions and to the inactive c-fos oncogene. Also, nitrogen mustard and methylnitrosurea damage is preferentially repaired whereas dimethylsulphate damage is not. NAAAF adducts do not appear to be preferentially repaired in this system. 32 refs.
- OSTI ID:
- 5264940
- Journal Information:
- Advances in Experimental Medicine and Biology; (United States), Vol. 283; ISSN 0065-2598
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHO CELLS
DNA REPAIR
METHYL NITROSOUREA
GENETIC EFFECTS
NITROGEN MUSTARD
SULFATES
BIOASSAY
DNA ADDUCTS
ENDONUCLEASES
NEOPLASMS
PYRIMIDINE DIMERS
ULTRAVIOLET RADIATION
ADDUCTS
ALKYLATING AGENTS
AMINES
ANIMAL CELLS
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CARBONIC ACID DERIVATIVES
DISEASES
DNA-ASE
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERASES
HYDROLASES
MUTAGENS
NITROSO COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHODIESTERASES
RADIATIONS
RECOVERY
REPAIR
SULFUR COMPOUNDS
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture
560300 - Chemicals Metabolism & Toxicology