Imaging of DNA damage repair using 53BP1 protein and establishment of therapeutic strategy for cancer treatment.

点击翻译按钮获取中文摘要

Tumor suppressor p53 Binding Protein 1(53BP1) is recruited rapidly to sites of DNA double-strand breaks (DSBs) and participates in the cellular response to DNA damage. We exploited property of 53BP1 that accumulate in DSB sites and developed biosensor detecting DNA damage using the specical form of 53BP1-GFP fusion protein that could express stably in the cell. Futhermore, we built a system that can identify the difference of cell cycle stage by intranuclear localization patterns of PCNA-DsRed. U2OS cell lines (U2RDP-LE53-21) expressing both these fluorescent fusion proteins make it possible to observe DSBs occurred in different cell cycle stage, these cells remain living. Here, we show how 53BP1 foci are observed in normal culturing conditions, and also how DSBs 53BP1 foci are induced by chemical agents such as Neocarcinostatine (NCS) or DNA Topoisomerase I inhibitor Camptothesin (CPT) that are well-known DSBs inducers. The number of 53BP1 foci was increased by these chemical agents and cell cycle distribution was prolonged compare to cells in normal culture condition. U2OS cell lines may be available for the screening chemotherapy drugs and radiosensitizers that induce DSBs in cancer cells.