Gene induction by gamma-irradiation leads to DNA fragmentation in lymphocytes

Journal Article · Sun Nov 15 04:00:00 EST 1987 · J. Immunol.; (United States)

OSTI ID:5650838

Sellins, K S; Cohen, J J

An early event in death of interphase lymphocytes exposed in vivo or in vitro to low doses of gamma-irradiation is the degradation of DNA into nucleosome-sized fragments. Induction of fragmentation required RNA and protein synthesis because actinomycin D and cycloheximide, respectively, are able to inhibit DNA fragmentation in irradiated lymphocytes. Studies adding cycloheximide and actinomycin D at various times postirradiation suggest that once the metabolic process is initiated within an individual cell it proceeds to completion. The reversible RNA synthesis inhibitor, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole inhibits DNA fragmentation in irradiated thymocytes. When this drug is removed after 6 hr, irradiated thymocytes proceed to fragment their DNA; this suggests that an inducing signal that is not simply mRNA persists within the irradiated cell for at least 6 hr after irradiation. In contrast to mitogen-activated T and B lymphoblasts, resting T and B cells show significant DNA fragmentation after exposure to 100 to 500 rad. At 2000 rad, all of the splenic subpopulations die rapidly via a different mechanism. By studying the mechanism of DNA fragmentation induced during the interphase death of lymphocytes, we hope to understand better the extreme sensitivity of resting lymphocytes to radiation and what may be the common final pathway of programmed cell death.

• Research Organization: Univ. of Colorado School of Medicine, Denver
• OSTI ID: 5650838
• Journal Information: J. Immunol.; (United States), Journal Name: J. Immunol.; (United States) Vol. 139:10; ISSN JOIMA
• Country of Publication: United States
• Language: English

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560120* -- Radiation Effects on Biochemicals
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL RADIATION EFFECTS
BLOOD
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GENE REGULATION
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IONIZING RADIATIONS
LEUKOCYTES
LYMPHOCYTES
MAMMALS
MATERIALS
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NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY
RNA
RODENTS
SOMATIC CELLS
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