Novobiocin treatment reverses radiation-induced alterations in higher-order DNA structure in L5178Y nucleoids

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Radiation Research; (United States)

DOI:https://doi.org/10.2307/3577943· OSTI ID:5011769

Kapiszewska, M; Lange, C S ^[1]

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1. Institute of Molecular Biology, Jagiellonian University, Krakow (Poland)

The authors have studied the effect of novobiocin treatment on radiation-induced damage and its repair in higher-order DNA structure in two mouse leukemia cell lines differing in their radiosensitivity, L5178Y-R (LY-R) and L5178Y-S (LY-S). They used the fluorescent halo technique to measure alterations in the superhelical density and the topological constraints of DNA in LY-R and LY-S nucleoids. The results for untreated cells show that both cell lines reached maximal DNA unwinding at the same concentration of propidium iodide (PI), whereas LY-S nucleoids were less efficient in their ability to rewind their DNA. The loop size did not differ significantly between the cell lines. Incubation of LY-R and LY-S cells with novobiocin at a concentration which does not influence survival (0.1 mM for 45 min), but inhibits DNA synthesis in LY-R cells (by 28%) to a greater extent than in LY-S cells (by 10%), also causes more DNA unwinding in LY-R nucleoids than in LY-S nucleoids. However, a decreased superhelical density was observed in nucleoids from both cell lines. Novobiocin applied before, and present during, irradiation prevents radiation-induced alterations in DNA supercoiling more efficiently in LY-R than in LY-S cells. The presence of novobiocin during the repair period increased DNA rewinding to levels not significantly different from control values in nucleoids from both cell lines.

• OSTI ID: 5011769
• Journal Information: Radiation Research; (United States), Journal Name: Radiation Research; (United States) Vol. 127:3; ISSN RAREA; ISSN 0033-7587
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BIOLOGICAL VARIABILITY
DISEASES
DNA REPAIR
DRUGS
EXPERIMENTAL NEOPLASMS
GENETIC VARIABILITY
IMMUNE SYSTEM DISEASES
IN VITRO
LEUKEMIA
MAMMALS
MICE
NEOPLASMS
RADIATION EFFECTS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RODENTS
TUMOR CELLS
VERTEBRATES