Bharti A K, Olson M O, Kufe D W, Rubin E H
Division of Cancer Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
J Biol Chem. 1996 Jan 26;271(4):1993-7. doi: 10.1074/jbc.271.4.1993.
DNA topoisomerase I (topo I) is involved in the regulation of DNA supercoiling, gene transcription, and rDNA recombination. However, little is known about interactions between topo I and other nuclear proteins. We used affinity chromatography with a topo I fusion protein to screen U-937 leukemic cell extracts and have identified nucleolin as a topo I-binding protein. Coimmunoprecipitation and other studies demonstrate that the interaction between topo I and nucleolin is direct. Furthermore, deletion analyses have identified the 166-210-amino acid region of topo I as sufficient for the interaction with nucleolin. Since nucleolin has been implicated in nuclear transport and in a variety of transcriptional processes, the interaction with topo I may relate to the cellular localization of topo I or to the known role of this topoisomerase in transcription.
DNA拓扑异构酶I（拓扑异构酶I）参与DNA超螺旋、基因转录和核糖体DNA重组的调控。然而，关于拓扑异构酶I与其他核蛋白之间的相互作用，人们了解甚少。我们使用带有拓扑异构酶I融合蛋白的亲和色谱法筛选U - 937白血病细胞提取物，并鉴定出核仁素是一种拓扑异构酶I结合蛋白。免疫共沉淀和其他研究表明，拓扑异构酶I与核仁素之间的相互作用是直接的。此外，缺失分析已确定拓扑异构酶I的166 - 210氨基酸区域足以与核仁素相互作用。由于核仁素与核运输和多种转录过程有关，与拓扑异构酶I的相互作用可能与拓扑异构酶I的细胞定位有关，或者与这种拓扑异构酶在转录中的已知作用有关。
