Abstract
Repair-proficient murine fibroblasts transfected with the denV gene of bacteriophage T4 repaired 70-80% of pyrimidine dimers within 24 h after exposure to 150 J/m2 ultraviolet radiation (UVR) from an FS-40 sunlamp. Under the same conditions, control cells repaired only about 20% of UVR-induced pyrimidine dimers. After UVR exposure, both control and denV-transfected cells exhibited some degree of DNA-synthesis inhibition, as determined by flow cytometric analysis of cell-cycle kinetics in propidium iodide-stained cells. DenV-transfected cells had a longer and more profound S phase arrest than control cells, but both control and denV-transfected cells had largely recovered from UVR effects on cell-cycle kinetics by 48 h after UVR exposure. Inhibition of DNA synthesis by UVR was also measured by determining post-UVR incorporation of bromodeoxyuridine (BrdU). The amount of BrdU incorporated was quantitated by determining with flow cytometry the quenching of Hoechst dye 33342 by BrdU incorporated in cellular DNA. DenV-transfected cells showed more marked inhibition of BrdU incorporation after low fluences of UVR than control cells. Differences between denV-transfected and control cells in cellcycle kinetics following UVR exposure may be related to differences in mechanisms of repair when excision repair of pyrimidine dimers is initiated by endonuclease V instead of cellular repair enzymes.
Original language | English (US) |
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Pages (from-to) | 163-176 |
Number of pages | 14 |
Journal | Mutation Research-DNA Repair |
Volume | 274 |
Issue number | 3 |
DOIs | |
State | Published - Sep 1992 |
Keywords
- Cell cycle progression
- DenV hene
- Flow cytometry
- Murine fibroblasts
- Pyrimidine dimers
- denV-transfected
ASJC Scopus subject areas
- Molecular Biology
- Toxicology
- Genetics