Exponential or shouldered survival curves result from repair of DNA double-strand breaks depending on postirradiation conditions

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3577143· OSTI ID:6969086

Frankenberg-Schwager, M; Frankenberg, D; Harbich, R

The yeast mutant rad54-3 is temperature conditional for the rejoining of DNA double-strand breaks, but cells do proliferate at both the restrictive and permissive temperatures. Thus, after irradiation with 30 MeV electrons, survival curves can be obtained which may or may not involve double-strand break rejoining under certain experimental conditions. Because of this special property of rad54-3 cells, it was possible to demonstrate that rejoining of radiation-induced double-strand breaks under nongrowth conditions yields exponential survival curves the slopes of which decrease as a function of the rejoining time. These survival data suggest that, under nongrowth conditions, the rejoining of double-strand breaks is an unsaturated process and lacks binary misrepair. In contrast, whenever rejoining of double-strand breaks occurs under growth conditions, shouldered survival curves are observed. This is true for immediate plating as well as for delayed plating survival curves. It is proposed that it is the unsaturated rejoining of double-strand breaks under nongrowth conditions, lacking binary misrepair, which is responsible for potentially lethal damage repair.

• Research Organization: Institut fuer Biophysikalische Strahlenforschung, Frankfurt (Germany, F.R.)
• OSTI ID: 6969086
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 114:1; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560130* -- Radiation Effects on Microorganisms
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL PROLIFERATION
DNA
DNA REPAIR
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
FUNGI
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
LEPTONS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PLANTS
RADIATION EFFECTS
RADIOINDUCTION
RECOVERY
REPAIR
SACCHAROMYCES
SACCHAROMYCES CEREVISIAE
STRAND BREAKS
SURVIVAL CURVES
TEMPERATURE DEPENDENCE
YEASTS