Absence of a dose-rate effect and recovery from sub-lethal damage in rad52 strain of diploid yeast Saccharomyces cerevisiae exposed to γ-rays

Reddy, Nandanuri M. S.; Anjaria, K.B.; Subrahmanyam, P. V.

doi:10.1016/0165-7992(82)90003-3

Cited by 14 publications

(3 citation statements)

References 17 publications

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“…An interesting, although not unexpected, new finding is the fact that the amount of dsb induced in rad52/rad52 cells remained unchanged when comparing dsb yields induced at HDR and LDR of y-irradiation . Moreover, in accordance with results of Reddy et al (1982), rad52/rad52 cell survival remains the same after equal doses at HDR and LDR and is not affected by post-treatment incubation of y-irradiated cells in non-growth conditions (data not shown) .…”

Section: Discussionsupporting

confidence: 92%

Repair of DNA Double-strand Breaks Induced inSaccharomyces CerevisiaeUsing Different γ-ray Dose-rates: A Pulsed-field Gel Electrophoresis Analysis

Dardalhon

Nohturfft²,

Méniel³

et al. 1994

International Journal of Radiation Biology

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We investigated the effects of gamma-ray exposures at high dose-rate (HDR, 23.2 Gy/min) and low dose-rate (LDR, 0.47 Gy/min) on survival and the induction of DNA double-strand breaks (dsb) in a diploid wild-type (D7) and the repair-deficient mutant strain rad52/rad52 of Saccharomyces cerevisiae. Analysis by pulsed-field gel electrophoresis (PFGE) using a contour homogeneous electric field apparatus revealed that, at HDR, in the range 0-400 Gy, dsb are induced as a linear function of gamma-ray dose. Liquid holding recovery in non-nutrient medium (LHR) for 48 h of wild-type cells treated at HDR, significantly increased survival and reduced the yield of dsb. Such changes did not occur in rad52/rad52 cells defective in the repair of dsb. Thus, in gamma-irradiated wild-type cells, an efficient repair of dsb is taking place during LHR. Treatments of wild-type cells at LDR resulted in higher survival and an approximately two-fold lower yield of dsb than at HDR. Such a dose-rate effect was absent in rad52/rad52 cells suggesting that, in wild-type cells during LDR exposures, significant amounts of dsb can be repaired. This repair could be very much accentuated by 48-h LHR of wild-type cells treated at LDR. The relationship observed between gamma-ray survival and dsb repair clearly indicates that increases in survival of wild-type cells, during LDR as compared with HDR exposures and after LHR, are strongly related to the repair of dsb.

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Section: Discussionsupporting

confidence: 92%

Repair of DNA Double-strand Breaks Induced inSaccharomyces CerevisiaeUsing Different γ-ray Dose-rates: A Pulsed-field Gel Electrophoresis Analysis

Dardalhon

Nohturfft²,

Méniel³

et al. 1994

International Journal of Radiation Biology

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“…An association between the lack of repair of DNA doublestrand breaks (as measured by sedimentation rate in sucrose gradients following lysis at pH 8), the lack of the recovery of colony-forming ability between split radiation doses, and the absence of dose-rate dependence, has been demonstrated in a radiation-sensitive strain of Saccharomyces cerevisiae, radS2 (17)(18)(19). Similarly, radiation-sensitive Chinese hamster ovary strains isolated by Jeggo and Kemp (20) have been shown to be deficient in the repair of DNA double-strand breaks (as measured by filter elution at pH 9.6) (21) and to lack dose-rate dependence (22).…”

Section: Discussionmentioning

confidence: 99%

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

Evans

Ricanati

Horng

1987

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

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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...

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“…In addition, the local heating effects of the optical tweezers on the cells were not critical in the present experiment. The morphological change of the irradiated cells was hardly observed in 15 h. There are some reports on RAD52 cell irradiation with conventional broad-field X-rays (Game & Mortimer, 1974) and gamma rays (Reddy, Anjaria, & Subrahmanyam, 1982;Rao & Reddy, 1982). RAD52 is sensitive to radiation due to a deficiency in the repair of double-strand breaks in DNA.…”

Section: Cell Irradiationmentioning

confidence: 99%

Single floating cell irradiation technique with an X-ray microbeam

Sato

Shimizu

Murata

2018

Journal of Radiation Research and Applied Sciences

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A single floating cell irradiation technique with X-ray microbeam has been developed for the microscopic research of radiation effects on floating cells in a liquid medium. This technique is a combination of X-ray microbeam and laser technologies. A preliminary experiment on the survival of budding cells of the yeast Saccharomyces cerevisiae (RAD52) was performed with the X-ray microbeam system. Micro-pits were fabricated on the bottom of a culture dish in a liquid medium, using green laser beams. The yeast cells were put into the micro-pits one by one by using focused infrared laser beams. A 50-kV X-ray microbeam 12 mm (FWHM) in diameter was propagated into the targeted yeast cell. The maximum dose rate on the targeted cell was estimated to be 0.09 Gy/s from the results of beam profile measurements and photonelectron transport calculations. The X-ray irradiation effect on the cell lethality was clearly observed for the cell exposed to X-rays of 100 Gy.

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Absence of a dose-rate effect and recovery from sub-lethal damage in rad52 strain of diploid yeast Saccharomyces cerevisiae exposed to γ-rays

Cited by 14 publications

References 17 publications

Repair of DNA Double-strand Breaks Induced inSaccharomyces CerevisiaeUsing Different γ-ray Dose-rates: A Pulsed-field Gel Electrophoresis Analysis

Repair of DNA Double-strand Breaks Induced inSaccharomyces CerevisiaeUsing Different γ-ray Dose-rates: A Pulsed-field Gel Electrophoresis Analysis

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

Single floating cell irradiation technique with an X-ray microbeam

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