Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Dikomey, Ekkehard; Franzke, J.

doi:10.1080/09553008614551311

Cited by 58 publications

(25 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lesions decay kinetics recorded for B 10 lens epithelial cells are best described by the sum of three exponential components, as has been shown for CHO cells [9][10][11], Com parison of half-times T(i), t(h) and T(m, with published values for CHO cells (table 2) are in good agreement with our results.…”

Section: Discussionsupporting

confidence: 82%

“…Obviously, in B 10 lens epithelial cells, double-strand breaks are in duced with the same efficiency as in CHO cells. Differences for the velocity of repair component III can be shown in our study when compared to the reports from the group of Dikomey [9][10][11]. Half-life time T(m) for B 10 lens epithelial cells shows more than 226 Baumstark-Khan/Aufderhcide/Rink DNA Strand Breaks in Bovine Lens Epithelial Cells twice the value obtained by CHO cells.…”

Section: Discussionsupporting

confidence: 51%

“…This assumption is based on the fact that the initial fraction (am: about 0.05) and the half-time of component III were found to be conform with measurements using the neutral sedimenta tion technique [8], The repair components I and II were discussed [10,11] as either repre senting two different classes of single-strand breaks or being attributed to primary single strand breaks induced by X-irradiation (I) and secondary single strand breaks caused by incision enzymes during excision repair (II).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

X-Ray Induced DNA Strand Break Induction and Rejoining in Cultured Bovine Lens Epithelial Cells

Baumstark‐Khan¹,

Aufderheide²,

Rink³

1992

Ophthalmic Res

View full text Add to dashboard Cite

DNA strand break induction and rejoining in cultured bovine lens epithelial cells were measured by the alkaline unwinding technique followed by hydroxyapatite chromatography. DNA damage is described in terms of dose effect curves for unwinding immediately after irradiation (0 min) and for unwinding after a recovery period (30 min). The dose effect curves obtained are purely exponential with Do values of 29.3 Gy (0 min) and 138 Gy (30 min), respectively. Rejoining data are given in terms of rejoining enhancement curves with half-times for overall rejoining being in the range from 4 to 10 min, independent of the dose. Kinetics of strand breaks are also presented in terms of decay curves, which are best described by the sum of three exponential components. The half-times of these components have been determined as τ_(I) ≈ 2 min, τ_(II) ≈ 15 min and τ_(III) ≈ 500 min. These components of damage decay curves are discussed in relation to cell killing.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Discussionsupporting

confidence: 51%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

X-Ray Induced DNA Strand Break Induction and Rejoining in Cultured Bovine Lens Epithelial Cells

Baumstark‐Khan¹,

Aufderheide²,

Rink³

1992

Ophthalmic Res

View full text Add to dashboard Cite

show abstract

“…Genetic studies quantitatively evaluating the kinetics of rejoining of radiation-induced DNA DSBs in wild type cells of higher eukaryotes [Dikomey and Franzke, 1986;Metzger and Iliakis, 1991], in mutants deficient in DNAPKcs [Nevaldine et al, 1997;DiBiase et al, 2000a], Ku [Wang et al, 2001b], or DNA ligase IV [Wang et al, 2001c], as well as after treatment with wortmannin [Wang et al, 2001a,b,c] provide evidence for the operation of at least two pathways of NHEJ with distinct properties that we have termed D-NHEJ and B-NHEJ [Wang et al, 2001b[Wang et al, , 2003] (see also ''Introduction''). D-NHEJ is fast (t 1/2 : 5-30 min), requires DNA-PKcs, Ku, DNA ligase IV, and probably Xrcc4 and rejoins DNA ends without excessive degradation [Wang et al, 2001b[Wang et al, , 2003].…”

Section: Discussionmentioning

confidence: 99%

Backup pathways of NHEJ are suppressed by DNA‐PK

Perrault

Wang

et al. 2004

J of Cellular Biochemistry

117

View full text Add to dashboard Cite

In cells of higher eukaryotes double strand breaks (DSBs) induced in the DNA after exposure to ionizing radiation (IR) are rapidly rejoined by a pathway of non-homologous end joining (NHEJ) that requires DNA dependent protein kinase (DNA-PK) and is therefore termed here D-NHEJ. When this pathway is chemically or genetically inactivated, cells still remove the majority of DSBs using an alternative, backup pathway operating independently of the RAD52 epistasis group of genes and with an order of magnitude slower kinetics (B-NHEJ). Here, we investigate the role of DNA-PK in the functional coordination of D-NHEJ and B-NHEJ using as a model end joining by cell extracts of restriction endonuclease linearized plasmid DNA. Although DNA end joining is inhibited by wortmannin, an inhibitor of DNA-PK, the degree of inhibition depends on the ratio between DNA ends and DNA-PK, suggesting that binding of inactive DNA-PK to DNA ends not only blocks processing by D-NHEJ, but also prevents the function of B-NHEJ. Residual end joining under conditions of incomplete inhibition, or in cells lacking DNA-PK, is attributed to the function of B-NHEJ operating on DNA ends free of DNA-PK. Thus, DNA-PK suppresses alternative pathways of end joining by efficiently binding DNA ends and shunting them to D-NHEJ.

show abstract

“…Because most of the DNA damage induced by irradiation is repaired very quickly, this repair pathway may be attributable to base excision repair. In fact, the irradiation-related DSBs are repaired with half-life of more than 2 hr (Dikomey and Franzke 1986) via nonhomologous recombination repair (Natarajan 2002). We investigated individual capacities to repair SSBs induced by irradiation.…”

Section: Parametersmentioning

confidence: 99%

Cytogenetic markers, DNA single-strand breaks, urinary metabolites, and DNA repair rates in styrene-exposed lamination workers.

Vodička

Tuimala

Štětina

et al. 2004

Environ Health Perspect

View full text Add to dashboard Cite

The effect of occupational exposure to styrene on frequencies of chromosomal aberrations and binucleated cells with micronuclei and on single-strand break levels in peripheral blood lymphocytes was studied in 86 reinforced plastic workers and 42 control individuals (including 16 maintenance workers with intermittent, low-dose exposure). In these individuals, the irradiationspecific DNA repair rates and the repair rates of 8-oxoguanines were investigated. We assessed the exposure by measuring the concentrations of styrene in air and in blood and of mandelic acid, phenylglyoxylic acid, 4-vinyl phenol conjugates and regioisomeric phenyl hydroxyethyl mercapturic acids in urine. All these parameters correlated with one another. No clear relationship was found between the styrene exposure and the frequencies of chromosomal aberrations. Binucleated cells with micronuclei were moderately related to the parameters of styrene exposure. We found a negative correlation between all exposure parameters and single-strand breaks. The positive correlation between exposure parameters and DNA repair rates suggests that particular DNA repair pathways may be induced by styrene exposure.

show abstract

Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Cited by 58 publications

References 41 publications

X-Ray Induced DNA Strand Break Induction and Rejoining in Cultured Bovine Lens Epithelial Cells

X-Ray Induced DNA Strand Break Induction and Rejoining in Cultured Bovine Lens Epithelial Cells

Backup pathways of NHEJ are suppressed by DNA‐PK

Cytogenetic markers, DNA single-strand breaks, urinary metabolites, and DNA repair rates in styrene-exposed lamination workers.

Contact Info

Product

Resources

About