Adelstein S J, Kassis A I
Harvard Medical School, Department of Radiology, Boston, MA, USA.
Acta Oncol. 1996;35(7):797-801. doi: 10.3109/02841869609104029.
The purpose of our studies is to elucidate the kinetics of DNA strand breaks caused by low-energy Auger electron emitters in close proximity to DNA. Previously we have studied the DNA break yields in plasmids after the decay of indium-111 bound to DNA or free in solution. In this work, we compare the DNA break yields in supercoiled DNA of iodine-125 decaying close to DNA following DNA intercalation, minor-groove binding, or surface binding, and at a distance from DNA. Supercoiled DNA, stored at 4 degrees C to accumulate radiation dose from the decay of 125I, was then resolved by gel electrophoresis into supercoiled, nicked circular, and linear forms, representing undamaged DNA, single-strand breaks, and double-strand breaks respectively. DNA-intercalated or groove-bound 125I is more effective than surface-bound radionuclide or 125I free in solution. The hydroxyl radical scavenger DMSO protects against damage by 125I free in solution but has minimal effect on damage by groove-bound 125I.
我们研究的目的是阐明低能俄歇电子发射体在紧邻DNA时引起DNA链断裂的动力学。此前我们研究了与DNA结合的或游离于溶液中的铟-111衰变后质粒中的DNA断裂产率。在这项工作中，我们比较了在DNA嵌入、小沟结合或表面结合后以及与DNA有一定距离时，靠近DNA衰变的碘-125在超螺旋DNA中的DNA断裂产率。将超螺旋DNA储存在4℃以累积来自125I衰变的辐射剂量，然后通过凝胶电泳将其解析为超螺旋、带切口的环状和线性形式，分别代表未受损的DNA、单链断裂和双链断裂。嵌入DNA或结合于小沟的125I比表面结合的放射性核素或游离于溶液中的125I更有效。羟基自由基清除剂二甲基亚砜可保护免受游离于溶液中的125I的损伤，但对结合于小沟的125I造成的损伤影响极小。
