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Naprawa okstydacyjnych uszkodzen DNA u Prokaryota

100%

Zastawny T. H.

nr 1

31-41

Zastosowanie mikroskopii skaningowo-tunelowej do badania struktury DNA

51%

Zastawny T. H. , Olinski R. , Olejniczak W.

1993

tom 17

3-7

Fractionation of DNA isolated from lymphocytes of patients under therapy with the antiblastic drug cis-diamminedichloroplatinum [II] using pulsed field gel electrophoresis

51%

Jaruga P. , Zastawny T. H. , Tujakowski J. , Olinski R.

tom 40

nr 1

Repair of gamma-ray-induced base damage in L5178Y sublines is damage type-dependent und unrelated to radiation sensitivity

51%

Kruszewski M. , Zastawny T. H. , Szumiel I.

Acta Biochimica Polonica

2001

tom 48

nr 2

The L5178Y (LY) murine lym phoma sublines LY-R and LY-S are dif fer en tially sen si tive to ion iz ing ra di a tion. The high ra di a tion sen si tiv ity of LY-S cells is re lated to impaired rejoining of DNA double strand breaks. We found previously that the g-ray-induced base dam age is higher in the more radiosensitive LY-S subline. Here, we ex am ine the role of the re pair of ion iz ing ra di a tion in duced base dam age in re la tion to the radiosensitivity dif fer ence of these sublines. We used the GS/MS tech nique to es ti mate the re pair rates of six types of base damage in g-irradiated LY cells. All mod i fied DNA bases iden ti fied in the course ofthis study were typ i cal for ir ra di ated chromatin. The to tal amount of ini tial base dam age was higher in the ra di a tion sen si tive LY-S subline than in the ra di a tion re sis tant LY-R subline. The re pair rates of 5-OHMeUra, 5-OHCyt, 8-OHAde were sim i lar in both cell lines, the re pair rates of FapyAde and 8-OHGua were higher in the radiosensitive LY-S cell line, whereas the re pair of 5-OHUra was faster in its radio resistant coun ter part, the LY-R. Al to gether, the re pair rates of the g-ray-induced DNA base dam age in LY sublines are re lated nei ther to the ini tial amounts of the dam aged bases nor to the dif fer en tial le thal or mutagenic ef fects of ion iz ing ra di a tion in these sublines.

Mutagenic specificity of imidazole ring-opened 7-methylpurines in M13mp 18 phage DNA

38%

Tudek B. , Graziewicz M. , Kazanova O. , Zastawny T. H. , Obtulowicz T. , Laval J.

nr 3

The most abundant lesion formed in DNA upon modification with methylating agents 7-methylguanine, under alkaline conditions is converted into 2,6-diamino-4-hydroxy-5N-methyl-formamidopyrimidine (Fapy-7MeGua). We have previously shown that treatment of dimethylsulfate methylated DNA with NaOH creates mutagenic base derivatives leading to a 60-fold increase in the frequency of A-->G transitions and a 2-3-fold increase of G-->T and G-->C transversions. We have analyzed which lesions lead to these mutations. We compared mutagenic spectra in the lacZ gene of M13mp18 phage DNA modified with dimethylsulfate and NaOH after selective elimination of damaged bases from molecules used for transfection into SOS-induced E. coli. Partial elimination of Fapy-7MeGua from phage DNA performed by its digestion with formamidopyrimidine-DNA glycosylase resulted in a 2-3-fold decrease of G-->T and G-->C transversions. Selective depurination of methylated bases (9 h, 37°C, pH 7,0) resulting in almost complete loss of 7MeAde as demonstrated by HPLC analysis of (3H)MNU alkylated phage DNA used as a probe, caused a dramatic, 9-fold decrease of A-->G transitions. Alkali-catalysed rearrangement of 7MeAde was followed by HPLC analysis of (3H)MNU alkylated polyA and polydA. After incubation of these oligonucleotides in NaOH, 7MeAde disappeared from both chromatograms, but only in polyA, 2 new peaks migrating with retention time different from that of 1MeAde, 3MeAde or 7MeAde were detected, suggesting formation of two rotameric forms of Fapy-7MeAde as observed for Fapy-7MeGua. Thus the miscoding lesion, giving rise to A-->G transitions derived from 7MeAde was Fapy-7MeAde. Fapy-7MeGua was at least an order of magnitude less mutagenic, but in SOS-induced cells it gave rise to G-->T and G-->C transversions.