Chromatin decondensed by acetylation shows an elevated radiation response
V-79 Chinese hamster lung fibroblasts exposed to 5 mM n-sodium butyrate were irradiated with 60Co gamma rays and cell survival was determined by the cell colony assay. In a separate set of experiments the acetylated chromatin obtained from these cells was irradiated and the change of molecular weight of the DNA was evaluated by alkaline sucrose density centrifugation. At a survival level of 10(-2) to 10(-4) cells exposed to butyrate were found to be 1.3-1.4 times more radiosensitive than control cells. Exposure of isolated chromatin to 100 Gy of 60Co gamma irradiation generated 0.9 +/- 0.03 single-strand breaks (ssb) per 10 Gy per 10(8) Da and 2.0 +/- 0.3 ssb/10 Gy/10(8) Da for control and acetylated chromatin, respectively. The elevated radiation sensitivity of chromatin relaxed by acetylation is in good agreement with previous results on chromatin expanded by histone H1 depletion. Packing and accessibility of DNA in chromatin appear to be major factors which influence the radiation sensitivity. The intrinsic radiation sensitivity of chromatin in various packing states is discussed in light of the variation of radiation sensitivity of whole cells in the cell cycle which incorporates repair.
- Research Organization:
- Univ. of Stellenbosch, Tygerberg (South Africa)
- OSTI ID:
- 6171700
- Journal Information:
- Radiat. Res.; (United States), Vol. 117:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BUTYRIC ACID
RADIOSENSITIVITY EFFECTS
CHROMATIN
ACETYLATION
STRAND BREAKS
RADIOINDUCTION
COBALT 60
DNA
FIBROBLASTS
GAMMA RADIATION
GENETIC RADIATION EFFECTS
HAMSTERS
LUNGS
MOLECULAR WEIGHT
RADIOSENSITIVITY
SURVIVAL TIME
ULTRACENTRIFUGATION
ACYLATION
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
CARBOXYLIC ACIDS
CENTRIFUGATION
CHEMICAL REACTIONS
COBALT ISOTOPES
CONNECTIVE TISSUE CELLS
ELECTROMAGNETIC RADIATION
GENETIC EFFECTS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MINUTES LIVING RADIOISOTOPES
MONOCARBOXYLIC ACIDS
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RESPIRATORY SYSTEM
RODENTS
SEPARATION PROCESSES
SOMATIC CELLS
VERTEBRATES
YEARS LIVING RADIOISOTOPES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture