Departments of Biotechnology, School of Life Sciences, University of Hyderabad, India.
Arch Biochem Biophys. 2011 Dec 15;516(2):128-37. doi: 10.1016/j.abb.2011.10.001. Epub 2011 Oct 10.
In the present study, the activity of Topoisomerase IIβ (TopoIIβ) is evaluated during peroxide induced double stranded DNA breaks (DSBs) repair in primary neurons. The results showed that the TopoIIβ levels were enhanced during recovery from peroxide mediated damage (PED) along with Ku70, PARP-1, pol beta, and WRN helicase. Furthermore, siRNA mediated knock-down of TopoIIβ in primary neurons conferred enhanced susceptibility to PED in neurons. DSBs in neurons are repaired through two pathways, one promoted by Ku70, while the other is by PARP-1 dependent manner. Participation of TopoIIβ in both pathways was assessed by analysis of the interaction of TopoIIβ with Ku70 and PARP-1 using co-immunoprecipitation experiments in extracts of neurons under peroxide treatment and recovery. The results of these studies showed a strong interaction of TopoIIβ with Ku70 as well as PARP-1 suggesting that TopoIIβ is associated both in Ku70 and PARP-dependent pathways in DSBs repair in primary neurons. The study has thus established that TopoIIβ is an essential component in DSBs repair in primary neurons in both Ku70 and PARP-1 dependent pathways. We suppose that the interaction of TopoIIβ may provide stabilization of the repair complex, which may assist in maintenance of tensional integrity in genomic DNA.
在本研究中，评估了拓扑异构酶 IIβ（TopoIIβ）在原代神经元中过氧化物诱导的双链 DNA 断裂（DSB）修复过程中的活性。结果表明，TopoIIβ 水平在过氧化物介导的损伤（PED）恢复过程中增强，与 Ku70、PARP-1、pol β 和 WRN 解旋酶一起增强。此外，在原代神经元中用 siRNA 介导的 TopoIIβ 敲低可使神经元对 PED 的敏感性增强。神经元中的 DSB 通过两种途径修复，一种由 Ku70 促进，另一种由 PARP-1 依赖性方式促进。通过在过氧化物处理和恢复后神经元提取物中使用共免疫沉淀实验分析 TopoIIβ 与 Ku70 和 PARP-1 的相互作用，评估了 TopoIIβ 在这两种途径中的参与。这些研究的结果表明 TopoIIβ 与 Ku70 和 PARP-1 之间存在强烈的相互作用，表明 TopoIIβ 与 Ku70 和 PARP-1 依赖性途径中的 DSB 修复有关。因此，该研究表明 TopoIIβ 是原代神经元中 Ku70 和 PARP-1 依赖性 DSB 修复的必需组成部分。我们假设 TopoIIβ 的相互作用可能提供修复复合物的稳定性，这可能有助于维持基因组 DNA 的张力完整性。
