Synzynys B I, Brozmanová J, Saenko A S
Neoplasma. 1987;34(1):55-9.
Sedimentation properties of nucleoids from HeLa cells cultured for 6 or 24 h with 10(-6) M fluorodeoxyuridine (FdUrd) were studied in neutral sucrose gradients. Independently on the presence and concentrations of ethidium bromide in the gradient, nucleoids from FdUrd treated cells sedimented farther than those from untreated cells. However, the maximum relaxation of supercoiled DNA, observed at the concentration of 5 micrograms/ml of ethidium bromide, was significantly lower in cells treated with FdUrd, which indicated that prior incubation with FdUrd did not increase the degree of DNA supercoiling but altered by some way the conformation of DNA in nucleus. Previously we have found, that treatment of HeLa cells with FdUrd resulted in the stimulation of DNA synthesis, which proved to be resistant to ultraviolet and gamma-irradiation. From the present results it is possible to suggest, that alterations of chromatine structure should be included in facilitating of DNA synthesis on DNA template damaged by ultraviolet or gamma irradiation.
在中性蔗糖梯度中研究了用10(-6)M氟脱氧尿苷（FdUrd）培养6小时或24小时的HeLa细胞核质体的沉降特性。与梯度中溴化乙锭的存在和浓度无关，FdUrd处理细胞的核质体比未处理细胞的核质体沉降得更远。然而，在溴化乙锭浓度为5微克/毫升时观察到的超螺旋DNA的最大松弛，在用FdUrd处理的细胞中显著更低，这表明预先用FdUrd孵育并没有增加DNA超螺旋程度，而是以某种方式改变了细胞核中DNA的构象。此前我们发现，用FdUrd处理HeLa细胞会导致DNA合成的刺激，这被证明对紫外线和γ射线照射具有抗性。从目前的结果可以推测，染色质结构的改变应该包括在促进紫外线或γ射线损伤的DNA模板上的DNA合成中。
