Characterization of repair of bleomycin-induced DNA damage in human chromatin

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6415682

Sidik, K

The characteristics of bleomycin-induced DNA damage and repair in intact human fibroblasts, and in fibroblasts that were reversibly permeabilized by short exposure to lysophosphatidylcholine (LPC), were examined. LPC treatment dramatically increases the dose effectiveness of bleomycin (BLM). Sufficient levels of single- and double-strand breaks were introduced into the DNA of permeabilized cells to yield a nucleosomal DNA pattern. We demonstrated that BLM is a short patch agent, since excision repair of BLM induced strand breaks involved the removal and reinsertion of less than 10 bases, as compared to >20 bases for long patch agents (e.g., UV radiation and bulky chemicals). Measurements of the initial nuclease sensitivity and subsequent nucleosome rearrangement of newly repaired regions of chromatin in intact and permeabilized cells following treatment with BLM were done in the presence and absence of aphidicolin (APC), an inhibitor of polymerase {alpha}. In intact cells, nucleosome rearrangement was not observed in the presence of APC. In the absence of APC, nucleosome rearrangement was also not observed if hydroxyurea (HU) was present after the insertion of repair patches (chased). If HU was absent during the chase period, rearrangement of chromatin structure at repair sites was observed. However, the rate of rearrangement was considerably slower than that observed for repair of long-patch agents. The slow rate of nucleosome rearrangement was also observed during repair induced by 1 {mu}g/ml BLM in the permeabilized cells. However, when higher concentrations of BLM were used, the rapid phase of nucleosome rearrangement was observed in permeabilized cells indicating nucleosome unfolding had taken place. These results suggest that, unlike long patch repair, significant nucleosome rearrangement does not occur during short-patch repair when the lesions are located primarily in linker regions of nucleosomes.

• Research Organization: Washington State Univ., Pullman, WA (USA)
• OSTI ID: 6415682
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMIDES
ANIMAL CELLS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTIMITOTIC DRUGS
ANTINEOPLASTIC DRUGS
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BLEOMYCIN
CHEMICAL COMPOSITION
CHROMATIN
CONNECTIVE TISSUE CELLS
DNA REPAIR
DRUGS
ENZYME ACTIVITY
ENZYMES
ESTERASES
ESTERS
FIBROBLASTS
FUNCTIONS
HYDROLASES
HYDROXY COMPOUNDS
HYDROXYUREA
LIPIDS
MAMMALS
MAN
NUCLEASES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHODIESTERASES
PHOSPHOLIPIDS
PRIMATES
RECOVERY
REPAIR
SOMATIC CELLS
STRAND BREAKS
VERTEBRATES