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RECOVERY OF SUBCHROMOSOMAL DNA SYNTHESIS IN SYNCHRONOUS V‐79 CHINESE HAMSTER CELLS AFTER ULTRAVIOLET LIGHT EXPOSURE
Author(s) -
Meechan P. J.,
Carpenter J. G.,
Griffiths T. D.
Publication year - 1986
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1986.tb09507.x
Subject(s) - chinese hamster , elongation , dna synthesis , irradiation , cell cycle , dna , thymidine , biophysics , cell culture , dna damage , cell , ultraviolet irradiation , ultraviolet light , cell division , microbiology and biotechnology , biology , chemistry , biochemistry , photochemistry , genetics , materials science , physics , ultimate tensile strength , nuclear physics , metallurgy
— Previous work obtained from Chinese hamster V‐79 cells indicated that, immediately following exposure, UV‐induced lesions acted as blocks to elongation of nascent strands, but gradually lost that ability over a 10 h period after exposure to 10 J/m 2 . The work reported herein attempted to examine possible cell cycle mediated alterations in the recovery of DNA synthesis. Kinetic incorporation of radiolabeled thymidine studies indicated that there may have been a more rapid recovery of DNA synthesis in cells irradiated in G 1 or G 2 vs cells irradiated in S phase. DNA fiber autoradiograms prepared from synchronous cells indicated that after irradiation in any phase of the cell cycle, the length of newly synthesized DNA was equal to control lengths 1 h after exposure to 5.0 J/m 2 (or 1 h after entering S phase for cells irradiated in G 1 or G 2 ). This observed recovery was not solely due to an excision process. No cell cycle mediated difference in the number of dimers induced or removed as a function of cell cycle position was observed. These results appear to be consistent with a continuum of effects, with initiation effects dominating the response at low fluences, gapped synthesis at intermediate fluences and elongation inhibition at high fluences. The fluences at which each event dominates may be cell‐line specific.