Resistance of the nucleosomal organization of eucaryotic chromatin to ionizing radiation. [/sup 60/Co]

Journal Article · Wed Sep 01 04:00:00 EDT 1982 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575889· OSTI ID:6654654

Chiu, S M; Oleinick, N L

The structural organization and radiation sensitivity of Tetrahymena chromatin under several conditions of modified transcriptional activity were investigated using the structure-specific nucleases, micrococcal nuclease and DNase I. Digestion of unirradiated nuclei by those nucleases proceeded with very similar kinetics and to a similar extent irrespective of the stages of growth of the cultures, except for the cultures in stationary phase, which became more resistant to DNase I digestion. Neither for suppression of total cellular RNA synthesis by actinomycin D nor the transient inhibition of only rRNA synthesis by 40 krad of ..gamma.. radiation affected the sensitivity of the chromatin of the nucleases. These results confirm that activity transcribing chromatin remains in an active conformation even when its function is temporarily inhibited, while more permanent repression of some genes during stationary phase appears to alter the chromatin and hence its susceptibility to DNase I. Actively transcribing ribosomal chromatin was found to be very sensitive to DNase I degradation compared to bulk chromatin; its sensitivity to DNase I was also not altered by 40 krad of ..gamma.. radiation, but was reduced in stationary phase. It is concluded that damage to DNA and/or chromatin resulting from ..gamma.. irradiation does not produce alterations in the nucleosome-level organization of chromatin which can be measured by micrococcal nuclease and DNase I.

• Research Organization: Case Western Reserve Univ., School of Medicine, Cleveland, OH
• OSTI ID: 6654654
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 91:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIODEGRADATION
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOSYNTHESIS
CHEMICAL REACTIONS
CHROMATIN
CILIATA
COBALT 60
COBALT ISOTOPES
CONFORMATIONAL CHANGES
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYMES
ESTERASES
GAMMA RADIATION
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
INVERTEBRATES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MICROORGANISMS
MINUTES LIVING RADIOISOTOPES
NUCLEASES
NUCLEI
NUCLEIC ACIDS
NUCLEOSOMES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PROTOZOA
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RNA
SYNTHESIS
TETRAHYMENA
TRANSCRIPTION
TRITIUM COMPOUNDS
YEARS LIVING RADIOISOTOPES