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Inhibition by hyperthermia of repair synthesis and chromatin reassembly of ultraviolet-induced damage to DNA

Journal Article · · Radiat. Res.; (United States)
DOI:https://doi.org/10.2307/3576524· OSTI ID:6024294

The authors have investigated the effects of hyperthermia treatment on sequential steps of the repair of UV-induced DNA damage in HeLa cells. DNA repair synthesis was inhibited by 40% after 15 min of hyperthermia treatment at 45/sup 0/C; greater inhibition of repair synthesis occurred with prolonged incubation at 45/sup 0/C. Enzymatic digestion of repair-labeled DNA with Exonuclease III indicated that once DNA repair was initiated, the DNA repair patch was synthesized to completion and that ligation of the DNA repair patch occurred. Thus, the observed inhibition of UV-induced DNA repair synthesis by hyperthermia treatment may be the result of inhibition of enzymes involved in the initiating steps(s) of DNA repair. DNA repair patches synthesized in UV-irradiated cells labeled at 37/sup 0/C with(/sup 3/H)Thd were 2.2-fold more sensitive to micrococcal nuclease digestion than was parental DNA; if the length of the labeling period was prolonged, the nuclease sensitivity of the repair patch synthesized approached that of the parental DNA. DNA repair patches synthesized at 45/sup 0/C, however, remained sensitive to micrococcal nuclease digestion even after long labeling periods, indicating that heat treatment inhibits the reassembly of the DNA repair patch into nucleosomal structures. 23 references, 3 figures, 2 tables.

Research Organization:
Univ. of California, San Francisco
DOE Contract Number:
AC03-76SF01012
OSTI ID:
6024294
Journal Information:
Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 100; ISSN RAREA
Country of Publication:
United States
Language:
English