Chromosomal Aberrations Induced by X-rays in Two Mouse Lymphoma (L5178Y) Sublines of Different Radiosensitivity

Bocian, Ewa; Boużyk, Elżbieta; Rosiek, O; Ziemba-Zółtowska, B

doi:10.1080/09553008214551261

Cited by 13 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The temperature sensitivity of the repair of pH 9.6-labile lesions in strain LY-S at 370C vs. 250C corresponds to the temperature sensitivity of cellular recovery occurring during postirradiation holding periods (3,5) and between fractionated doses ofirradiation (4,5,14) in strain LY-S. A deficiency in the repair of pH 9.6-labile lesions and/or frank doublestrand breaks at 370C may also explain the limited dose-rate dependence of the survival of strain LY-S (15) and the increased induction of chromosome aberrations in strain LY-S following irradiation in comparison to strain LY-R (16).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Deficiency in DNA repair in mouse lymphoma strain L5178Y-S.

Evans

Ricanati

Horng

1987

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The production and repair of radiation-induced DNA damage were measured by filter elution in strains of mouse lymphoma L5178Y cells differing in their sensitivity to ionizing radiation. The induction of radiation-induced damage, as measured by filter elution at pH 12.1, 9.6, and 7.2, was similar in the resistant-strain LY-R and the sensitive strain LY-S. The repair of single-strand breaks and alkali-labile sites, as measured by filter elution at pH 12.1 at various times after irradiation, was somewhat slower in strain LY-S than in strain LY-R, although after a 20-min repair period the extent of repair was equal in the two strains. However, when filter elution was performed at either pH 9.6 or pH 7.2, the repair of x-radiation-induced damage was much less extensive in strain LY-S than in strain LY-R. We have assumed that the extent of filter elution at pH 9.6 is a measure of the occurrence of frank double-strand breaks as well as closely opposing single-strand breaks and pH 9.6-labile sites (and combinations thereof), and that the extent of elution at pH 7.2 is a measure of the occurrence of frank double-strand breaks alone. If these assumptions are correct, the results suggest that the sensitivity of strain LY-S to the cytotoxic effects of ionizing radiation is caused by a deficiency in the ability of this strain to repair frank double-strand breaks and pH 9.6-labile lesions. The repair of pH 9.6-labile lesions was temperature sensitive in strain LY-S, as previously found for cellular recovery processes in this strain. Two independent radiation-resistant variants of strain LY-S, isolated after protracted exposure of LY-S cells to low-dose-rate radiation, showed a deficiency in the repair of pH 9.6-labile lesions similar to that observed in strain LY-S. However, the repair of frank double-strand breaks was more extensive in the radiation-resistant variants than in strain LY-S and was similar in extent to that occurring in strain LY-R after a 60-min postirradiation incubation. The results suggest that there is a difference In the nature of DNA damage measured by filter elution at pH 9.6 vs. pH 7.2 and that a deficiency in the repair of pH 9.6-labile lesions does not contribute to cell lethality in the case of the radiation-resistant variants. The radiation resistance of these variants in comparison to strain LY-S may be due at least in part to recovery of the ability to rejoin frank DNA double-strand breaks.Mouse lymphoma strain L5178Y-S (LY-S) was isolated in 1961 by Alexander and Mikulski (1) following a spontaneous increase in sensitivity of a culture of LY5178Y cells to the cytotoxic effects of ionizing radiation. The parental culture was designated LY-R to differentiate it from the newly isolated sensitive strain. LY-S cells have been shown to be deficient in cellular recovery processes following exposure to ionizing radiation [reviewed by Beer et al. (2)], particularly when postirradiation incubation was carried out at 370C (3-5). Conflicting reports have appeared concerning the difference in the abi...

show abstract

Section: Discussionmentioning

confidence: 99%

“…No marked differences were observed between the strains in the radiation-induced production of DNA damage as measured by Radiation Dose, Gy [12][13][14][15][16][17]1986, Las Vegas, NV. Fig.…”

mentioning

confidence: 99%

Deficiency in DNA repair in mouse lymphoma strain L5178Y-S.

Evans

Ricanati

Horng

1987

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Time needed to rejoin 50% 5 min 4 min of DNA single strand breaks, 2 or 10 Gy (7 rays) alkaline DNA unwinding 100 Gy (X rays) alkaline 13 min 40 rain sedimentation Change in partition between None Marked two polymer aqueous phases (24 h after 10 Gy X) Evans et al 1983Szumiel 1979Szumiel et al 1981Bocian et al 1982Johanson et al 1982K6rner et al 1977Wtodek and Szumiel 1981 A defect in the enzymatic repair system of LY-S cells cannot at present be altogether excluded, however, different susceptibility to agents that are known to modify chromatin structure suggests that some features of the chromatin architecture could be responsible for accessibility of lesions to repair enzymes and hence, for the observed sensitivities to X rays and UV light. As stated by Williams (1978) "protein conformational sensitivities to temperature, pressure and salt make all proteins into thermometers, barometers, and osmometers'.…”

Section: Ly-r Ly-s Referencementioning

confidence: 98%

Ion content and the response of L5178Y-R and L5178Y-S cells to X rays and ionophore A23178

Szumiel

Wlodek

Lustyik³

1984

Radiat Environ Biophys

View full text Add to dashboard Cite

We examined the response of L5178Y-S (radiosensitive, LY-S) and L5178Y-R (radioresistant, LY-R) lymphoblasts to X-irradiation with concomittant treatment with divalent cation ionophore, A23187 (3 h or 5 h, 5 micrograms/ml). Cells treated with A23187 alone progressed through the cell cycle more slowly than the untreated cells and their cloning efficiency was reduced. In both cell strains the ionophore prolonged duration of the postirradiation mitotic delay. Radiation-induced inhibition of DNA synthesis was reversed by A23187 in LY-S but not in LY-R cells. Cells subjected to the ionophore treatment survived X-irradiation in almost the same way as untreated cells, as if the effect of A23187 treatment were reversed by irradiation. There was also a reversion in the ion content: A23187 caused a marked increase in Na+ content and a decrease in K+ content, irradiation itself did not change the ion content, whereas in the A23187-treated cells it restored almost the same pattern as that found in the control cells. We found less Mg2+ ions in LY-S cells after treatment with A23187 and A23187 + X than in LY-R cells, in relation to untreated (control) cells. These observations point to the possible importance of ion transport for recovery from radiation damage.

show abstract