Role of repair mechanisms in the variations of ultraviolet and $gamma$- radiation sensitivity during the cell cycle of Schizosaccharomyces pombe

Journal Article · Sat Dec 01 04:00:00 EST 1973 · Radiat. Res., v. 56, no. 3, pp. 528-539

OSTI ID:4358394

Fabre, F

The lethal effects of uv and gamma rays were studied on synchronized cells of S. pombe with different defects in their repair pathways: UVS A cells do not excise pyrimidine dimers; UVS 1 cells are probably deficient in a repair mechanism related to recombination. UVS/sup +/ (wild-type) cells, after uv and gamma -irradiation, and UVS A cells after gamma -irradiation, are the most resistant in the G2 phase of the mitotic cycle. These observations support the existence of a repair mecharism, which acts on uv- and gamma -induced lesions before DNA replication and is different from that of excision-resynthesis. After uv irradiation, it requires the participation of an incision enzyme also involved for excision repair. The uv response of UVS A cells is constant during the cycle, suggesting the presence of a repair mechanism acting during or after DNA replication. The uv resistance of UVS 1 cells decreases progressively from the beginning of the G2 to the end of the S period. This is interpreted in terms of delay available for excision repair. The practically constant response to uv of UVS A and of the double mutant UVS 1A, and to gamma -rays of UVS 1A cells indicates that when variations occur, they are mainly due to diffurential repair abilities within the cycle. (auth)

• Research Organization: Institut du Radium, Orsay, France
• NSA Number: NSA-29-015872
• OSTI ID: 4358394
• Journal Information: Radiat. Res., v. 56, no. 3, pp. 528-539, Journal Name: Radiat. Res., v. 56, no. 3, pp. 528-539; ISSN RAREA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*YEASTS-- RADIOSENSITIVITY
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL REPAIR
CELL CYCLE
DIMERS
DNA
ENZYMES
GAMMA RADIATION
MUTANTS
N48310* --Life Sciences--Radiation Effects on Microorganisms- -Basic Studies
PHOTON BEAMS
PYRIMIDINES
RADIOSENSITIVITY EFFECTS
RESPONSE MODIFYING FACTORS
ULTRAVIOLET RADIATION RADIOSENSITIVITY EFFECTS