Inhibition of DNA replication by ultraviolet light

Journal Article · Sun Aug 01 04:00:00 EDT 1976 · Biophys. J.; (United States)

DOI:https://doi.org/10.1016/S0006-3495(76)85735-9· OSTI ID:7224225

Edenberg, H J

DNA replication in ultraviolet-irradiated HeLa cells was studied by two different techniques: measurements of the kinetics of semiconservative DNA synthesis, and DNA fiber autoradiography. In examining the kinetics of semiconservative DNA synthesis, density label was used to avoid measuring the incorporation due to repair replication. The extent of inhibition varied with time. After doses of less than 10 J/m/sup 2/ the rate was initially depressed but later showed some recovery. After higher doses, a constant, low rate of synthesis was seen for at least the initial 6 h. An analysis of these data indicated that the inhibition of DNA synthesis could be explained by replication forks halting at pyrimidine dimers. DNA fiber autoradiography was used to further characterize replication after ultraviolet irradiation. The average length of labeled segments in irradiated cells increased in the time immediately after irradiation, and then leveled off. This is the predicted pattern if DNA synthesis in each replicon continued at its previous rate until a lesion is reached, and then halted. The frequency of lesions that block synthesis is approximately the same as the frequency of pyrimidine dimers.

• Research Organization: Massachusetts Inst. of Tech., Cambridge
• OSTI ID: 7224225
• Journal Information: Biophys. J.; (United States), Journal Name: Biophys. J.; (United States) Vol. 16:8; ISSN BIOJA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
DIMERS
DNA REPLICATION
ELECTROMAGNETIC RADIATION
HELA CELLS
IRRADIATION
NUCLEIC ACID REPLICATION
RADIATION EFFECTS
RADIATIONS
ULTRAVIOLET RADIATION